Following trial, comedian's still on TV (4,4)
I believe the answer is:
test card
'still on tv' is the definition.
(a test card is a still image broadcast on TV)
'following trial comedian's' is the wordplay.
'following' means one lot of letters go next to another.
'trial' becomes 'test' (synonyms).
'comedian' becomes 'card' (card can mean a humorous person).
'test' next to 'card' is 'TEST-CARD'.
(Other definitions for test card that I've seen before include "Cricket scoring system" , "shown on TV in an idle moment?" , "Detailed pattern for checking TV picture" , "what's not usually watched on TV" .)