The Halo Master Chief Collection's new Season 6: Raven update (full patch notes here) adds a ton of new features and cosmetics, including the often requested mouse and keyboard support.

After many long years, Xbox gamers can finally play Halo with a mouse and keyboard. The option is included in the new Season 6 update (a mighty 50GB download) and offers secondary key binding as well. We haven't tried out the M&KB options just yet so we can't comment on how well they support high DPI mice or specific gaming-oriented keyboards.
- Mouse & Keyboard support for Xbox - Console players can now play using a mouse and keyboard with this feature supported for Xbox.
- Secondary bindings for Mouse & Keyboard - Any action can now be bound to multiple inputs while using mouse and keyboard.
- Field-of-View (FOV) and Crosshair Position options for Xbox - Field-of-View (FOV) and Crosshair Position options are now available on all Xbox platforms, including 120Hz supported devices.
Season 6 also makes some other fundamental gameplay tweaks including new FOV and crosshair-position options. One of the most flavorful additions is the myriad of cosmetics; 343i has added Mjolnir armor suits from Fireteam Raven (the Halo arcade game) and Halo Online, the previously Russian-only Halo shooter.

Here's a brief rundown of the cosmetics:
- New armors based on Fireteam Raven and Halo Online for Halo 3
- New back accessory customizations for Halo 3
- New animated visors for Halo 3
- New animated nameplates
- New techsuit colors

343i also ported over a map from Halo Online and inserted it into Halo 3. It's called Waterfall, and it's the first new Halo 3 map in many, many years. The studio says they have plans to make new Halo maps as they double-down on MCC support:
"We have plans to bring more maps into MCC in future seasons. We are investigating what is possible for each game and what additional maps we can bring in,"MCC design director Max Szlagor told GameSpot.
Season 6: Raven is out now on Xbox consoles and PC.
With Season 6, we've got a heap of new content shipping out, and we can't wait for you to get your hands-on it. This time around you can look forward to:
- 100 new tiers of content for Season 6 (including brand new armor, back accessories, animated visors, and more)
- Waterfall, a Halo Online map now playable in custom games for Halo 3
- The Exchange
- A brand-new game variant for Halo 2: Anniversary, Halo: Reach, and Halo 4 - Escalation Slayer
- The ability to change your teams mid-game in custom matches across all titles in MCC
- And more!