Concat(
    Split(LookUp(colADD_General, ID = intLastID,GenHotTopics),", "), ThisRecord.Value, ", "
)
&
With
(
    { x: Concat(
            Filter(ComboBoxHotTopics.SelectedItems, ThisRecord.Data <> Blank()),    
            ThisRecord.Data,", "
        )
    }, If(IsBlank(x),"", ", " & x)
)