[PC] [2010-present] Multiplayer co-op game that had a gimmick fight at the end where everyone is fighting each other

I forgot a game's name where the core gameplay was to reach a certain objecive by co-op gameplay, probably 2-4 players or even more. And I remember at the end (either win or loose condition) there was a gimmick arena fight where everyone was thrown into an arena to fight each other. It could be top down or FPS I don't remember that...

Sorry for the loose description but that is all I remember. Thanks for all the comments!