Código:
Sub InsertarComentarios()
Dim R As Range, C As Range, I As Range, B As Comment
On Error Resume Next
Set R = Application.InputBox("Selecciona el rango de celdas cuyos valores se utilizarán como comentarios:", "Aprendiendo eXcel365", Type:=8)
On Error GoTo 0
If R Is Nothing Then Exit Sub
On Error Resume Next
Set C = Application.InputBox("Selecciona el rango de celdas donde se insertarán los comentarios:", "Aprendiendo eXcel365", , Type:=8)
On Error GoTo 0
If C Is Nothing Then Exit Sub
For Each I In C
If Not IsEmpty(R.Cells(I.Row - C.Rows(1).Row + 1, I.Column - C.Columns(1).Column + 1).Value) Then
Set B = I.AddComment(R.Cells(I.Row - C.Rows(1).Row + 1, I.Column - C.Columns(1).Column + 1).Value)
End If
Next I
MsgBox "Los comentarios se han insertado correctamente.", , "Aprendiendo eXcel365"
End Sub