It seems as though CD Projekt Red is not in the business of resting on its laurels, with the studio recently celebrating the 13th anniversary of The Witcher 3: Wild Hunt with a newly revealed update and DLC for the game, working on both The Witcher 4 and a Witcher 1 remake, Cyberpunk 2, and apparently a new co-op Witcher game, which has started to appear in rumors of late. The rumors of a co-op Witcher game started with a spin-off game called under the codename Sirrius, that would be primarily a single-player game with optional multiplayer layered over the top. Project Sirrius seems to align with rumors of a new Witcher co-op game, as reported by MP1st. The biggest change from previous games in the Witcher universe is that this will be a multiplayer co-op experience, with players working together to hunt and take down monsters.

CDPR has yet to reveal the game or any gameplay details, but the rumors purport that the co-op Witcher game will be free-to-play and launch for both PC and mobile—presumably both Android and iOS. Allegedly, Sirrius will be set in 1230, when Geralt was already active as a witcher. However, players will not play as Geralt or another established witcher. Instead, the game will feature typical ARPG customization and a matching skill tree. Combat will largely be skills-based, relying on dodging, blocking, parrying, and executions, and players will be able to select from different witcher schools for their class, combat style, and skills. The aforementioned skills and combat system will include Signs and casting as well as potion brewing. CD Projekt Red hinted in a March earnings report that the company's next collaboration with Scopely, a mobile developer the studio worked with on prior Witcher mobile games, would certainly not launch in 2026, so a 2027 or even 2028 launch date seem more realistic, depending on how far along development is.