According to Xbox insider Shpeshal Ed, Ubisoft's games could arrive to Xbox Game Pass by the end of 2021. However, the deal will not include all games from the Ubisoft+ plan.
Some Xbox insiders already suggested that Ubisoft's games could join Xbox Game Pass, similarly to how EA Play games were added to the service. At the moment, the Ubisoft+ subscription only offers one plan, which includes all Ubisoft games, new and old.
Of course, it's hard to expect that every single Ubisoft game will end up on Game Pass but some titles most definitely could. And according to reliable Xbox insider Shpeshal Ed, Ubisoft's game may arrive to Game Pass by the end of 2021.
"Only got confirmation of Ubisoft's games on Game Pass by year's end," Ed wrote on Discord (screenshots below). Furthermore, Ed predicts that everything up to Immortals Fenyx Rising could arrive to Game Pass.
When asked if Microsoft plan to increase the pricing of Xbox Game Pass anytime soon, Ed replied that probably won't be the case but it's possible that Microsoft will have separate tiers for both EA and Ubisoft games on Game Pass.
As always with unconfirmed info, take this as a rumour or speculation until we get an official confirmation from Microsoft or Ubisoft. That being said, Shpeshal Ed has been a reliable source for Xbox related stuff in the past and it would not be surprising if this turns out to be true. It certainly makes sense for both Ubisoft and Xbox.