Userform ComboBox populating Comboboxes from worksheet data

What I am trying to accomplish is having the agent name populate cbAgentName combobox based on cbMU as well as populating cbAgent combobox. Both these comboxes should act the same as cbSkName and lbMSN. If in cbMU I choose 100 then cbAgentName and cbAgent should populate with all agents that are in the group # 100 based on columns A:C
Also I need the lbData to populate as well but only with the agents that have skillnames and levels that do not match
So summary is lbData should show agents name, skill name, skill level sys1 and sys2 only if the skill levels don’t match but I want the data to be pulled from the columns A:G based on what they should retrieve and the lbData should stay blank till cbMU chosen then display one instance of each agent with mismatched skills. the cbAgent and cbAgentName can be filled like what the way lbMSN is setup but again one instance of each agent not multiples like on the worksheet.
Some background:
Listbox (lbMSN) & ComboBox (cbSkName) rely on what a person chooses under ComboBox (cbMU)

Worksheet GtoICheck has columns and rows that I need to populate Listbox (lbData) ComboBox (cbAgentName)
All columns are static and cannot be changed as the empty columns seen do have data that I had to remove.
The names of agents are dynamic so the range can vary even as deep as from A2:H1500
Columns R:T are the Sys1 reference and are the accurate point of reference
Column F pulls data for the agent but from a different worksheet
Column G is formula based to look for agent in Column A and pull that agents skill Level from another sheet but for this sample I placed the values in.
The colored cells (normally are conditional formatted) but just colored to reflect what is green is accurate and what is red is not. So level1 9 in Sys1 is =Level1 in Sys2 thus cell is green. (9=1, 5=5 and 0=0 are all accurate) but 9=5, 5=0, 0=9, 0=5 are not accurate thus they are red or would be in the conditional format formula

What I did so far is add an array in cbMU so when 100 is chosen it displays the skill names in lbMSN and cbSkName. You will also notice the skill level in lbMSN is also displaying but if you take a look at the array it is really time consuming to try and align as what I did. If there is a way to improve on the code I used I look forward to it as I have over 40 skills, skill names and levels that are needed to be added.
Columns R:T have the Sys1 MU’s, Skill names and levels and ideally should feed the cbMU results in lbMSN and cbSkName instead of using the array
I really need help on the first initial problem for the cbAgentName and cbAgent to populate the way I need it too. The array would be a bonus and accepted with total gratitude as well.

To give an idea for the array used and my apologies for ugly it looks

Private Sub cbMU_Change()
Dim idx As Long
Dim arr As Variant
Dim isa As Long
Dim rra As Variant
idx = cbMU.ListIndex
If idx = -1 Then Exit Sub ' nothing selected, so exit
Select Case cbMU.Value
Case "100"
arr = Array("Skill1 1", "Skill2 1", "Skill3 5", "Skill4 1", "Skill5 1", "Skill6 5")
Case "112"
arr = Array("Skill9 1", "Skill15 5", "Skill16 5", "Skill17 1")
End Select
lbMSN.List = arr
isa = cbMU.ListIndex
If isa = -1 Then Exit Sub ' nothing selected, so exit
Select Case cbSkName.Value
Case "100"
rra = Array("Skill1", "Skill12", "Skill3", "Skill4", "Skill5", "Skill6")
Case "112"
rra = Array("Skill9", "Skill15", "Skill16", "Skill17")
End Select


cbSkName.List = arr

End Sub

Any help is greatly appreciated.

You can loop through column C and get the results to populate the other combobox

Private Sub cbMU_Change()

    Dim Rng As Range
    Dim c As Range
    Dim s As String
    s = Me.cbMU

    Me.cbAgentName.Clear

    Set Rng = Range("C:C").SpecialCells(xlCellTypeConstants, 23)

    For Each c In Rng.Cells
        If c = s Then
            Me.cbAgentName.AddItem c.Offset(, 2).Value
        End If
    Next c

End Sub

Davesexcel that worked great in the sample with the exception it duplicates the name and I need to somehow add in the '.RemoveDuplicates' code but when I copied the code into the original it doesn't do what it's supposed to like the sample. I had to adjust the offset to 5 to pull from column H for the agents names but it worked great in the sample. Any chance you can let me know what the '23' is after 'xlCellTypeConstants' so I have a better understanding of the code? Any chance to adjust the code to look in column A for the name or should I just leave it as column H using offset 5?

I updated the code you supplied in the sample to include cbAgent and it works great for both comboboxes (except the duplicates at this point) but as mentioned it doesn't work in the original workbook and both comboboxes as they are blank and no error messages either.

well I thought I had the code to remove the duplicates in the combobox named cbAgentName but it didn't work.
I am not certain how to or if it's possible to add .removeduplicate in the following code as I keep getting errors

Me.cbAgentName.AddItem c.Offset(, 1).Value

so I attempted updating the vba code in the cbAgentName combobox using the following code but it does nothing and doesn't error out
What am I doing wrong or missing? I don't want the sheet duplicates removed. Just want individual names showing in the cbAgentName combobox
Here is the code I thought would work (not my code but adapted it to my userform and sheet)

Option Explicit


Sub cbAgentName_Change()
  Dim AllCells As Range, Cell As Range
    Dim NoDupes As New Collection
    Dim i As Integer, j As Integer
    Dim Swap1, Swap2, Item
    
'   The items are in B2:B3000
    Set AllCells = Range("B2:B3000")
    

'   The next statement ignores the error caused

    On Error Resume Next
    For Each Cell In AllCells
        NoDupes.Add Cell.Value, CStr(Cell.Value)
'       Note: the 2nd argument (key) for the Add method must be a string
    Next Cell

'   Resume normal error handling
    On Error GoTo 0

'   Sort the collection (optional)
    For i = 1 To NoDupes.Count - 1
        For j = i + 1 To NoDupes.Count
            If NoDupes(i) > NoDupes(j) Then
                Swap1 = NoDupes(i)
                Swap2 = NoDupes(j)
                NoDupes.Add Swap1, before:=j
                NoDupes.Add Swap2, before:=i
                NoDupes.Remove i + 1
                NoDupes.Remove j + 1
            End If
        Next j
    Next i

'   Add the sorted, non-duplicated items to cbAgentName
    For Each Item In NoDupes
        ufSkillsAudit.cbAgentName.AddItem Item
    Next Item

End Sub

Anyone have suggestions to my dilemna?
Ultimately if I can get this working I will adapt the working code to include the cbAgent combobox but thought it would be good to work on one at a time.
I have alot of work left on this userform and once the duplicate removal works then I am going to look at whoever I choose in cbAgent when clicked will show in the lbData listbox with only the values that have mismatches from the conditional format I have on the sheet; but not on the sample I supplied.

Thank you to anyone who is willing to help a learning older guy

Like this.

Private Sub cbMU_Change()
    sn = Sheets("GtoICheck").Range("C:C").SpecialCells(xlCellTypeConstants, 23).Resize(, 2)
    With CreateObject("scripting.dictionary")
        For i = 2 To UBound(sn)
            If sn(i, 1) = cbMU Then x0 = .Item(sn(i, 2))
        Next
        cbAgentName.List = Application.Transpose(.keys)
    End With
End Sub

You probably are using that damn Option Explicit.

Add this at the top of the code.

Dim sn, x0,i as long

Private Sub cbMU_Change()
    Dim sn, x0, i As Long
    cbAgentName.Clear
    cbAgent.Clear
    sn = Sheets("GtoICheck").Range("C:C").SpecialCells(xlCellTypeConstants, 23).Resize(, 2)
    With CreateObject("scripting.dictionary")
        For i = 2 To UBound(sn)
            If sn(i, 1) = CDbl(cbMU.Value) Then x0 = .Item(sn(i, 2))
        Next
        If .Count Then cbAgentName.List = Application.Transpose(.keys)
    End With
End Sub

Try the example file. It does how I understand your query.
Opening the UF some Comboboxes are prefilled. Selecting a MU populates AgentsName and Agents and gives all filtered searchresults from GtoICheck in Left side Listbox.
When filling all Comboboxes on the right and clicking Write writes results to Audit Data Tracker and fills below listbox with all data present there.
Don't know what you want with bot other Listboxes ?

For that I should need to see the original file or your example file should exactly match the layout, sheetnames, objectnames etc... as the original.

Glad you got it running.
You're welcome and thanks for rep+.