Ubisoft has announced that it will “share details on a new next-gen IP currently in development” at Gamescom.
The publisher isn't holding a proper conference, so it probably won't be revealed in some grand fashion, unless of course it makes an appearance at either Sony's or Microsoft's presser. We've heard rumblings about a game called "Child of Light" from Ubisoft Montreal in the past, so it could be related to that.
What sort of new IP are you hoping Ubisoft shows off at Gamescom 2013? Be creative, and share your ideas in the comments below.