In a blog post on Halo Waypoint, founder and head of 343 Industries, Bonnie Ross, made the announcement:
Holmes says he has “loved every moment” working on Halo, but that he felt it was time to move on to something new. Holmes has yet to announce where he will be going next, whether he will join an existing independent game studio or create his own.
Taking his place as studio head of the FPS team at 343 will be Chris Lee, who served as Lead Producer on Halo 4 and Executive Producer on Halo 5: Guardians. Holmes said the franchise is in good hands with Lee:
As for Halo, it is celebrating its 15th anniversary with a special REQ pack and playlist in Halo 5. The developer has also teased the next DLC pack for Halo 5, and Chris Lee said soon 343 will be talking more about a free content update coming to Halo 5: Guardians and its Forge mode.
Virtually nothing is known about Halo 6, but the studio has confirmed that the next entry in the franchise is in development. The next game to come out in the Halo franchise is the real time strategy game Halo Wars 2, slated to release in February 2017.
Halo 5: Guardians is available now, exclusively on Xbox One.
Source: Halo Waypoint (via GameSpot)