Yes, an honest-to-goodness Borderlands sequel (not a pre-sequel) appears to be on the horizon. Gearbox has posted a teaser for what's likely to be the Borderlands 3 reveal at PAX East on March 28th. It doesn't say much about the game, but there's not much mystery here -- not when it features Borderlands' signature cell-shaded art and a "3" at the top.
Gearbox teases 'Borderlands 3' reveal on March 28th
It's only been five years since the last game.
There have been hints as to what the title will involve. Company chief Randy Pitchford demonstrated early Unreal Engine 4 technology for "the next Borderlands game" at GDC in 2017, and it was evident the visuals wouldn't be a huge departure from the post-apocalyptic look of earlier releases, even if they'd be much prettier. The question is whether or not the gameplay will receive a similar tune-up. Borderlands broke ground with its approach to a shooter-RPG hybrid (such as its method of generating unique equipment), but there's no guarantee the game mechanics will evolve to match.
— Gearbox Official (@GearboxOfficial) March 12, 2019