https://www.gamespot.com/articles/xbox-game-pass-new-games-for-september-2018-announ/1100-6461505/

It's almost September, and that means the next wave of additions to the Xbox Game Pass library are coming out soon. There are 10 titles being added to the catalog in September, including some big first-party games such as Halo: The Master Chief Collection and Quantum Break. These add to the more than 100 games (across Xbox One and Xbox 360) that are already available in the library.

The Master Chief Collection, which originally launched in 2014, is biggest Halo package ever released. It includes remastered versions of Halo: Combat Evolved and Halo 2, in addition to Halo 3 and Halo 4. All of the multiplayer maps for each game are also included. If you're playing on Xbox One X, the game looks better and loads faster.