https://www.gamespot.com/articles/even-some-xbox-360-games-receive-xbox-one-x-enhanc/1100-6454283/

Xbox One games won't be the only ones to look better when played on Xbox One X. Enhancements will also be available for a select number of Xbox 360 games, Microsoft confirmed today.

Halo is notable because Halo: The Master Chief Collection is in line for Xbox One X enhancements. Microsoft has extensive plans to offer improvements for existing Halo games.