Macro returning string, while i want array

This version will return an array. If you are calling from a sheet, you need to select the range of cells where you want the value returned and enter =FindSeries(..) as an array formula, using Ctrl-Shift-Enter (Cmd+Return for Mac) to enter the formula.

Public Function FindSeries(TRange As Range, MatchWith As String)
    Dim retArray as Variant
    For Each cell In TRange
        If cell.Value = MatchWith Then
            x = x & cell.Offset(0, 1).Value & ", "
        End If
    Next cell
     
    retArray = Split(Left(x, (Len(x) - 2)),", ")
    
    FindSeries = retArray
End Function