Goran Bukvic, a freelance artist, uploaded some work on Artstation that look to be from a cancelled Batman game, presumably Warner Bros.' "Project Sabbath." These images appear to show how Batman would have looked if the project finished development
Goran Bukvic's Artstation page includes five images related to the cancelled game, though Bukvic didn't mention any project titles and developers in his pieces. It could be from another project, though we're assuming it's Project Sabbath given similarities to other leaked images.
The other artwork shows villains such as Two-Face, Poison Ivy, Gorilla Grodd, Black Mask and an aged Dick Grayson, all of whom were going to be included in Project Sabbath. That's all we know about the cancelled game, though, since WB never released official details on it.
Cancelled Batman Arkham Knight Sequel Concept Art Surfaces
As of now, Batman voice actor Kevin Conroy has long confirmed in the WizardWorld Nashville convention that he wasn't hired to do another Batman: Arkham series title after Arkham Knight. Conroy confirmed this back in 2017 which was two years after Arkham Knight's release.
Both WB Games Montreal and Rocksteady Games have their own games to work for 2022: Gotham Knights and Suicide Squad: Kill the Justice League. Gotham Knights has no ties to the Arkham games, and while Suicide Squad will reportedly carry on the Arkham story, Batman is not confirmed as playable so far.