Last year's episode of the series also pays tribute to Valve's store as part of Ubisoft's confrontation with exclusivity. We don't know the exact release date, but it will be available this month.
It can be said that it is unexpected for the French Ubisoft announcedAssassin's Creed Mirage will be released on Steam this month, but that would be a big lie. Until now, the game has only been available to PC audiences on the Epic Games Store and Ubisoft's own store. Mirage's Steam page is now live, but the exact release date is still unknown.
Part of the change in Ubisoft's strategy is to break the exclusive agreements that Epic used to have with other publishers, and which it plans to conclude in the future. At the same time, the French publisher is officially returning to Steam releases with the next AC game, so it ultimately makes sense that this part would also join Valhalla a year after Mirage's release.
Interestingly, Assassin's Creed Mirage was released for iPhone before it entered Valve's store. It's not yet known exactly when Bassem's Adventure will be available on Steam, but it's likely that we'll get the Shadowdrop skin.