PlayStation All-Stars Battle Royale developer SuperBot Entertainment is recruiting for what seems to be another game in the franchise. A job listing at the Sony studio hints that whatever it's working on, it involves mashing up various PlayStation franchises once again.
The listing (via CVG) suggests that the new art director will be responsible for unifying a vision to bring together "an incredibly wide range of artistic styles." It also says the art director would represent the developer to IP holders and the publisher, to make presentations on how the various characters, environments, and assets would fit.
The job never explicitly calls the project a sequel to PlayStation All-Stars, but it's definitely a PlayStation crossover of some kind so All-Stars 2 only makes sense. The listing even mentions taking a project from concept art to completion while developing new tech, which would seem to rule out DLC or expansions for the first game.