Highlight activecell's row and column

I went a similar route.

A Sheet specific macro enters the activecell address into p1

That triggers two conditional formats.

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Range("P1").Value = Target.Address
End Sub

Formula:

=COLUMN()=COLUMN(INDIRECT($P$1))

Formula:

=ROW()=ROW(INDIRECT($P$1))