CEO and President of Gearbox Software, Randy Pitchford, gives us a taste of what the franchise has in store for us next. Pitchford supplemented in his interview on the Nerdist podcast, that more Borderlands 2 DLC is planned as well as a whole new brand for next-gen consoles.

"We did a Season Pass for Borderlands 2, and the Season Pass was like, 'hey, if you buy the Season Pass we're going to be doing four campaign DLC's, but you can get all four of them for the price of three if you buy upfront,'" Pitchford explains. "So everyone has this expectation that those would be the four DLC's and then that's it. We're going to do more. We're going to do some other things. We don't have details yet about it exactly."

He also added, "I'm not ready to announce what other things are" but that the recently-released Tiny Tina's Assault on Dragon Keep "won't be the end of it." He concluded saying, "we've got more stuff in the hopper that we're planning and that we're getting pretty excited about. So if you are a Borderlands fan, you don't have to be afraid that that's the end of it."

(Here is Tiny Tina's Assualt on Dragon Keep DLC preview, released in June.)​

Apart from Borderlands, Pitchford, confirmed that Gearbox is working on building a whole new brand which will land around the time of the release of Xbox One and Playstation 4.​
"We are building an original IP for the next generation that we'll announce sometime later," he revealed. "Obviously we have Borderlands, we've got Brothers in Arms, we've got Duke Nukem and we acquired Homeworld recently. So we have all of those great brands, but we're actually creating some new things that we'll announce. So that will be something to look forward to."​
Take note that Pitchford didn't give a time that this mysterious new IP it will be released, though it likely will won't be any time this year, since we didn't hear it at E3.​
In my opinion, Borderlands and Borderlands 2 are some of the most amusing and obsessive games I've played. With future DLC, I hope Gearbox is at helm. The first 3 DLC's were convivial, even if there is a degree in between those and Tiny Tina. Either way, more DLC!​