Article about yours truly making comeback? That’s an idea! (5)
I believe the answer is:
theme
'that's an idea' is the definition.
(theme is a kind of idea)
'article about yours truly making comeback?' is the wordplay.
'article' becomes 'the' (the definite article in English).
'about' is an insertion indicator.
'yours truly' becomes 'me' (the person who set this crossword).
'making comeback?' shows that the letters should be reversed in order.
'me' backwards is 'em'.
'the' enclosing 'em' is 'THEME'.
(Other definitions for theme that I've seen before include "Thread, melody" , "[(type of) PARK]" , "Leitmotiv" , "Short melody" , "Topic; melody" .)