Refers to the calendar year following the current one. Can be used as a noun or adverbially without a particle.
来年、日本に行く予定です。
I plan to go to Japan next year.
来年の春に卒業します。
I will graduate next spring.
I really want to pass the JLPT next year, no matter what.
来年 means 'next year', the opposite time reference from 本年, which means 'this year'.