Xbox reportedly explored having Call of Duty studio Sledgehammer Games develop a Halo multiplayer game

Microsoft

Microsoft is said to have explored bringing Activision's Sledgehammer Games in to develop a multiplayer-focused Halo title, according to reports from insider Rebs Gaming corroborated by Windows Central's Jez Corden. A prototype was built and then quietly shelved, but conversations are reportedly ongoing.

The details:

Sledgehammer Games built a basic prototype for a Halo multiplayer pitch in June 2026. The prototype was described as a "blockout," testing only foundational mechanics like player movement. It was cancelled in early July. No game has been greenlit.
Rebs Gaming reports that despite the prototype being dropped, Microsoft is still actively exploring the proposition of having Activision help develop Halo games. Jez Corden had separately floated the same rumour weeks earlier.
The next Halo game is believed to be codenamed Project Ecker and is expected to be a multiplayer-focused experience, distinct from the single-player Halo: Campaign Evolved.
The context matters: Halo: Campaign Evolved was developed with the help of around 15 external studios according to the same reports, and the franchise's original creator recently said the absence of PvP from that game was "poor planning." Halo's internal studio, Halo Studios, appears to be leaning heavily on outsourcing as it rebuilds.
Sledgehammer's multiplayer pedigree includes Call of Duty: WWII and Call of Duty: Vanguard, which drew over 30 million players.

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