https://www.polygon.com/2017/9/21/16345530/halo-3-xbox-one-backward-compatible-now-available-odst

Microsoft just made a major addition to the Xbox One’s backward compatibility library: Halo: Combat Evolved Anniversary, Halo 3, Halo 3: ODST and Halo 4 are now supported in the program, the company announced today.

Halo studio 343 Industries said in early July that support for these games was on the way. All four titles are already playable on Xbox One — Halo Anniversary, Halo 3 and Halo 4 were included in 2014’s Halo: The Master Chief Collection, and 343 released an upgraded version of Halo 3: ODST’s campaign on Xbox One in May 2015. (It was available free for some Master Chief Collection players as a make-good for the compilation’s botched launch.) The other Halo game that Bungie made, 2010’s Halo: Reach, has been backward compatible since December 2015.