It might be seen as a curious move when you can simply pick up the Halo: Master Chief Collection, but as announced back at E3, all of the Xbox 360 Halo games have now been added to the Xbox One’s library of backward compatible titles.
This includes Halo 3, Halo 3: ODST, Halo 4 and Halo: Combat Evolved Anniversary, with Halo: Reach having been added back in 2015. You’ll be able to play multiplayer online between console generations, and all of the DLC content was made free on the Xbox Store earlier this year, meaning there’s no barriers between groups.
If you own the games digitally, they will simply appear in the “Ready to Install” section of your Xbox One, while you just need to insert the disc if you own it physically. The Halo 3: Mythic disc that was bundled alongside ODST can also be used to get online with the Halo 3 multiplayer.
Source: Halo Waypoint