What does "現代修真" mean?
百度 has lots of books under 现代修真小说完本, they seem to be about immortals. 

修真 seems to be a Taoist phrase, '道教中，学道修行，求得真我，去伪存真为“修真”。' I think you're pretty close with 'cultivating the truth / the true reality / the true self'。