Hike in sunshine, we hear (5)
I believe the answer is:
raise
'hike' is the definition.
(I know that hike can be written as raise)
'sunshine we hear' is the wordplay.
'sunshine' becomes 'rays'.
'we hear' indicates a 'sounds like' (homophone) clue.
'rays' is a homophone of 'RAISE'.
'in' acts as a link.
(Other definitions for raise that I've seen before include "Make greater" , "Haul up" , "Put up" , "Cultivate by growing" , "better?" .)