A new Injustice game was rumored due to repeated news around the franchise though the initial job listing would suggest that it is a long way off.
In June a job listing from Warner Bros. Games, that is still listed as of October 2020, for a Principal Software Engineer to work on the graphics of a next-gen vision of the Mortal Kombat and Injustice franchise.
In July it was brought up when the author of the Injustice tie-in comics teased a continuation of that series. The later announcement, of Injustice Year Zero, was not connected to a new game.
In August a teaser image was posted by BossLogic ahead of the DC FanDome event using the title Injustic3.