https://www.gamespot.com/articles/halo-infinite-adds-a-co-developer/1100-6460773/

Halo Infinite will be a joint development from 343 Industries and SkyBox Labs, it was announced today. The Vancouver-based SkyBox Labs has a long history of working with 343, as it worked on Halo 5: Forge for Windows 10 and did the work on Halo 5's Xbox One X enhancements. It sounds like SkyBox's efforts for Halo Infinite will be more substantial.

In a news release, SkyBox said it will work alongside 343 on "features across the game including AI, gameplay, networking, and cutting-edge graphics features."