If you mean the one that's prominently featured in the trailer, it's "Seasons of Love." The movie soundtrack is not listed yet, but you can look at the Original Cast Recording on or somewhere else.
Hi! First-time poster here, yay! :). Has anyone seen the new "Rent" trailer? The new one has a kind of medley of "Another Day" and "Will I?" Anyone know the song title and if I can get it anywhere? Thanks a bunch!
Have a great one!

The song is entitled "Finale B". The Rent film soundtrack is already out, you can find it there, as well as on ITunes, I believe. I hope this helps