Bishop coming over with pop group (4)
I believe the answer is:
band
'pop group' is the definition.
(I've seen this before)
'bishop coming over with' is the wordplay.
'bishop' becomes 'B' (chess abbreviation).
'coming over' says to put letters next to each other (in a down clue, some letters go over others).
'with' becomes 'and'.
'b'+'and'='BAND'
(Other definitions for band that I've seen before include "A collection of musicians in ring" , "See 23" , "Pop group; stripe" , "Loop; rock group" , "Belt; group of musicians" .)