Tron Legacy doesn't even hit theaters until December, but Disney has so much faith in the franchise, that they are moving forward with developing the next Tron movie. Disney has hired LOST writers Edward Kitsis and Adam Horowitz to write the sequel to Legacy. They also wrote the Tron Legacy film that is coming out at the end of the year.
There's obviously no details on what the next Tron film will be about. Hell, we haven't even seen Tron Legacy yet! Insiders say that Kitsis and Horowitz are working on a way to round the story into a trilogy. This isn't really any surprising news, we've heard Disney is very excited for the rebirth of the Tron franchise, and that they love what they've seen of Tron Legacy. They've been talking about making more Tron movies for awhile now, but now they're actually putting words into action.
As of right now there are no deals in place with Tron Legacy director Joseph Kosinski or the film's cast members to return, but options were placed in the original deals, and Disney surely would hope to reunite all the elements if the film ends up being a hit.
One thing at a time. It's cool that they are working on a sequel, but we still need to see Tron Legacy first. I'm still hoping it lives up to my expectations.