Along with busting caps of both the bullet and knee variety, Deadpool is known for being one of the deadliest members of the X-Force - a collection of mutant antiheroes in the Marvel comics universe (not the MCU, just to be clear). Basically, they're the X-Men without scruples. And if a report from ComicBook.com is true, we could see an X-Force movie tease in the post-credits scene of Deadpool 2.
The site claims that three major characters will make an appearance during Deadpool 2's post-credits scene: Feral, Shatterstar, and Sunspot. In case those names don't ring any bells, let me summarize. Feral is basically a humanoid cat, Shatterstar is an extraordinarily agile fighter thanks to his hollow bones, and Sunspot can manipulate solar energy to grant himself all manner of abilities.
Each of these characters has been affiliated with X-Force in the past, though I admit I'm surprised they didn't go with a better-known team. I figured an X-Force movie team would've more contemporary members like Warpath, Hepzibah, or Fantomex. Or heck, even find a way for Wade's girlfriend Vanessa to unlock mutant abilities and become Copycat (her identity from the comics). Or employ time-travel shenanigans so X-23 can join. But hey, I'm no Hollywood writer.