Rainbow Six Siege does feature cross-play, but only for consoles in the same family, and between PC and Stadia.

Is Crossplay coming to siege?

While Rainbow Six Siege crossplay is coming, it's not going to be the unified experience you see in games like Call of Duty: Warzone or Apex Legends. Here, the crossplay experience will be limited by platforms – meaning PC and console players will never be placed in the same game.

Is siege cross platform between Xbox and PS4?

Is Rainbow Six Siege cross-platform PS4, PS5, and Xbox? Yes, if you have a PS4 or PS5, you can play with your friends who are on the other system (Xbox). The game will be cross-platform, meaning if one had a PS4/PS5 and someone else has an Xbox they could play together in multiplayer.