https://www.gamespot.com/articles/rainbow-six-siege-operation-grim-sky-release-date-/1100-6461522/

Year 3, Season 3 of Tom Clancy's Rainbow Six Siege kicks off soon with the release of Operation Grim Sky. While the expansion is already available to try out on the game's test server, Ubisoft has now revealed when it'll go live for all players on PS4, Xbox One, and PC: September 4.

Like previous Operations, Grim Sky introduces two new Operators to the game: Maverick and Clash. Both hail from different organizations and fall under different classes. Maverick is an Attacker from America who can use stun grenades and a blowtorch (and who has already been nerfed). Clash, meanwhile, is a Defender from Great Britain. She's the first Defender in the game to wield a shield, which also comes equipped with a taser.