Set before Borderlands 2 before Handsome Jack became the CEO of Hyperion, Borderlands: The Pre-Sequel stars a new team of four unique classes, all of whom are under Jack's employ in assisting him in his plans for power. However what's new over the prior two Borderlands games is the classes are all pre-existing within the universe, which includes the playable debut of Claptrap.
Borderlands: The Pre-Sequel! is to be developed by 2K Australia, as opposed to Gearbox who created and developed the previous two games in the series.
While not a direct numbered sequel, the high sales and positive reception to Borderlands 2 lead to the development of another Borderlands game, though one that went through a much quicker development schedule than between the first two games. However due to Gearbox currently working on different projects, it was instead handed over to 2K Australia instead.
Randy Pitchford of Gearbox stated during the announcement that they do not wish to develop the game for Playstation 4 or Xbox One for economical reasons, and believes that they'd rather focus exclusively on the previous generation due to the higher install-base.