Let It be? Track initially included in songs given at concert (4)
I believe the answer is:
stet
'let it be?' is the definition.
(printing instruction to let a piece of text stand)
'track initially included in songs given at concert' is the wordplay.
'initially' suggests taking the first letters.
'included in' means one lot of letters goes inside another.
'songs given at concert' becomes 'set' (as in a set list at a concert).
The initial letter of 'track' is 't'.
't' put inside 'set' is 'STET'.
(Other definitions for stet that I've seen before include "Ignore crossing" , "It may stand" , "Leave in, as text" , "Cancellation of correction" , "Ignore correction" .)