https://wccftech.com/halo-the-master-chief-collection-next-gen-free-upgrade/

Halo The Master Chief Collection will receive a free next-gen upgrade shortly after the Xbox Series X and Series S release worldwide.

Today, Microsoft confirmed via the Xbox Official Twitter profile that this free upgrade will be released on November 17th. The upgrade will bring 120 FPS support for both single-player campaign and multiplayer, split-screen improvements, and up to 4K resolution on the Series X.