Halo MCC does work on Steam Deck, provided you play the right mode. At the time of writing, only a portion of Halo: The Master Chief Collection is supported on Steam Deck. Here’s the need-to-know info on getting single-player and multiplayer Halo to work on Steam Deck.
How to play Halo MCC single-player on Steam Deck
Halo MCC single-player doesn’t require any workarounds on the Steam Deck. If you want to play any single-player Halo campaign on Steam Deck, simply download the game from your Steam library and hit play.
How to play Halo MCC multiplayer on Steam Deck
Thanks to anti-cheat incompatibilities with Steam OS, anti-cheat is disabled on Halo MCC when playing on Steam Deck. This means Halo MCC multiplayer matchmaking is not playable by default, and you won’t receive achievements in single-player campaigns. However, local co-op campaigns and custom games will work.
343 Industries and Valve have both confirmed they are working on an anti-cheat fix, but there is no estimated date at the time of writing.
If you’re looking for your Halo multiplayer fix, Halo Infinite‘s multiplayer is fully compatible with Steam Deck. However, you may need to tweak the version of Proton you’re running to play it.
