Mystery Dungeon and Pokémon are two popular series both in the west and in Japan, and when you put the two together you get one of the best-selling spin-off series in Nintendo history. Take a look at this brief Japanese trailer from Nintendo Direct for Pokémon Super Mystery Dungeon.
Pokémon Mystery Dungeon is an exploration RPG series that has the player take the role of a Pokémon instead of a Trainer, living in a Pokemon village where all the different monsters help each other out with their unique skills. You still make teams and explore dungeons, recruiting other Pokémon rather than capturing them. Your avatar can be any of the starter Pokémon from the history of the series, including the franchise mascot Pikachu, and if the trailer is any indication, you will be seeing plenty of legendary Pokémon from past series as well. The series has traditionally released the Mystery Dungeon titles internationally, but so far there has been formal confirmation on a North American release date. However, the game is slated for a fall release in Japan.