Emily Blunt, Benicio Del Toro and Josh Brolin are reprising their characters for the sequel to 2015 drama Sicario.
The crime thriller revolved around an FBI attempt to take down a Mexican drug cartel with the help of a shady character, played by Del Toro.
"We're in full development with the studio," producer Molly Smith told The Hollywood Reporter. "I just got a draft (of the script), and we're really excited."
Fellow producer Trent Luckinbill added, "We can't reveal the plot, but you'll see them (Blunt, Del Toro and Brolin) all come back.
"You have such a great character with Benicio, who was as dark as he was... That character resonates so well with audiences. People want to know what happened to him, so it's a perfect foray for us to explore."
A director for the sequel has yet to be named, but the producers hope Denis Villeneuve will return.
"He's a busy man, but he's certainly part of the process with us right now," Luckinbill added.