It's expected to be unaffected (7)
I believe the answer is:
natural
This clue is a double definition.
'it's expected' is the first definition.
(thesaurus)
'be unaffected' is the second definition.
(similar in meaning)
'to' acts as a link.
(Other definitions for natural that I've seen before include "Regular" , "Innate, inborn" , "Organic" , "Frank < , twenty-one" , "Unforced" .)