In 2010, the first proper film in the Predator franchise (that wasn't of the "Alien versus" variety) arrived in the form of Predators, a sequel that had been written just a few years after Predator 2 and sat in a drawer. Produced by Robert Rodriguez, the film mixed up the formula of the franchise by taking a platoon of characters off Earth and dropping them into the hunting grounds of the titular aliens. Though the film was met with decent critical reception and grossed over $125 million at the global box office, no follow-up came until 2018's The Predator (which didn't even acknowledge the 2010 feature).
There was talk of a proper Predators follow-up after its release and though they failed to materialize we now know what might have been with the sequel. Speaking in a new interview with AvPGalaxy (H/T Bloody Disgusting), Predators co-writer Alex Litvak offered up the details, revealing plenty of meaty information on what they'd planned for a sequel.
The film would have picked up after the 2010 feature and once again starred Adrien Brody as Royce, a former special ops soldier turned mercenary, and Alice Braga's Isabelle, a sniper. At the top of the movie they'd still be living on the Predator hunting planet, rescuing new targets that are being dropped onto the grounds as prey for the Predators. The tribe of humans devise a plan to escape by being captured by Super Predators and infiltrating their ship under the guise of being prisoners, leading to Litvak's elevator pitch for the sequel "Die Hard on a Predator ship."
On the ship, as the humans worked to find the controls and fly it back to earth they would encounter other Predators and a variety of creatures on the ship's "alien zoo." The conclusion to the film however would have been the stuff of legend on the big screen as it would tie the Predator and Alien franchises together in a seamless way.
"At the end of the day we win, we get back to Earth, we land and we realise it’s the future!" Litvak wrote. "All along we thought this was happening now, but what if these guys have been on ice for 300 years? The hatch opens, and the Space [Colonial] Marines come in!...That was how we merge the two worlds – the Alien and Predator world finally merge and bring the Space Marines into the story. He (studio head at Fox) goes “I f***ing love it!” We just kept waiting for him to say “go write this”…I can’t speak to that, but I guess some stars never lined up so that version never got off the ground."
As of this writing it's unclear what future the Predator franchise will have since the rights to the films were gained by The Walt Disney Company as part of their acquisition of 20th Century Fox. Despite its cult popularity, it's hard to imagine Disney making Predator a priority on the big screen, though they have already announced the comic book rights to the property are moving to Marvel Comics.