Getting an error when trying to make a workbook opened from sharepoint active

I'm not sure why.. but when I try to make a workbook that I opened, from sharepoint, to be active it gives me a run time error specifically on this line of code..

Workbooks(wb.Name).Activate

Here is my full code.

Sub CheckOut()
Dim xlApp As Excel.Application
Dim wb As Workbook
Dim xlFile As String
xlFile = "https://microsoft.sharepoint.com/blah/blah/blah"

    If Workbooks.CanCheckOut(xlFile) = True Then
        Workbooks.CheckOut xlFile
        Set xlApp = New Excel.Application
        xlApp.Visible = True
        Set wb = xlApp.Workbooks.Open(xlFile, , False)
        MsgBox wb.Name & " is checked out to you."

        Else
        MsgBox "You are unable to check out this document at this time. Please make sure it is not checked out to anyone, including you."
    End If

Workbooks(wb.Name).Activate

ActiveWorkbook.Save
ActiveWorkbook.Close
ActiveWorkbook.CheckIn

End Sub

Any help would be greatly appreciated!

Thanks in advance.