As reported by PCGamesN, a number of job listings for the studio have just gone live, with none of them mentioning Gotham Knights.
Some job descriptions do offer a window into what WB Games Montreal are crafting with the 3C Game Designer being responsible for "designing and driving development of player characters for a third-person open world action game".
Other job listings, such as the Senior Gameplay/Animation Programmer lists the game as a "new IP, AAA title".
It isn't clear if this references a completely new original IP, or a new IP based on a DC property or character, given that a number of job listings reference animating or working on DC characters.
As for what this new game is, your guess is as good as ours, but fans have been hoping for a Superman game for years. We have yet to see any evidence that WB Montreal is developing a DC or Superman game but it would be a nice follow up after Gotham Knights releases in 2022.
To stay up to date with all the latest Gotham Knights news, be sure to keep an eye on our hub as we get closer to next year's release.