Sony posted a list of playable games for PlayStation 4 and Vita on their Gamescom website, which included Journey. Since then, the list has been taken down. A member of NeoGAF was able to capture and post it.
Journey is an indie game developed by thatgamecompany. It was released in 2012 and was critically praised, earned Game of the Year awards from some sites like IGN.
I finally got the chance to play Journey earlier this year and it was terrific. I love being able to play short games like that and it’s an easy decision to bring it to the PS4.