One big bit of news coming out of Japan D23 is a new Marvel Tsum Tsum game coming in Spring 2016!
Based on what we have found out this game will *not* be created by LINE (the developers of the current game) but instead be made by a company named Mixi. They have a current game called "Monster Strike" and it sounds like the new Marvel Tsum Tsum game will have some of the same game play elements of "Monster Strike"
In Monster Strike you collect Monsters and battle with other "Monsters". You can upgrade and combine Monsters as well as team up with other players to have multi-player battles. So it sounds like it will be VERY different from the current game.
It is unknown if this game will be exclusive to Japan to start (like the original game) or if it will be available internationally.
We will be sure to keep you updated!
Basic app details from Famitsu.com