[2019] Can i upgrade my rainbow six siege from standard edition to ultimate edition?

Originally posted by Fenor: but when I will launch the game on uplay, it Will be shown on steam that I actually in game?

No, it will not. I suppose you could add it as a Shortcut on Steam to do so.

Originally posted by Fenor: So when I buy the Ultimate edition on Uplay I can't launch game on steam?

Nope. It is a different edition of Siege. You'd have to launch it through Uplay specifically.