Xbox and Ps4 cooperative?

Vi
2

1. You can play Rainbow Six Siegen with Xbox and PS4 at all times?

2. Are there other games besides Fortnite that XBOX people and PS4 people can play together?

Pa

No.
I think Rocket League and Modern Warfare, I'm not aware of any others, at least many are not.

Ch

I can still think of World of Warships.