Microsoft and 343 Industries have announced that Halo 3: ODST will be coming to PC on September 22nd as part of The Master Chief Collection, making the game available on Steam, Microsoft Store and through Xbox Game Pass for PC. Halo 3: ODST is not to be confused with Halo 3, which came out two years earlier. It is a standalone expansion to the third Halo, set between Parts 2 and 3.
The entire campaign is remastered and Firefight, the games signature multiplayer mode has been updated as well. It also gets improved graphics with 4K and 60+ FPS, FOV customization and support for mouse and keyboard.
Halo 4 will be the next game to arrive as part of Halo: The Master Chief Collection, after which Halo 5: Guardians will be the only Halo title to lack a PC release. At this time, Microsoft has not revealed any official plans to bring Halo 5 to PC.