TERMINATOR 6 IS A SEQUEL TO TERMINATOR 2
Both Warner Bros. and Paramount Pictures attempted to reboot the Terminator franchise and spawn new trilogies of their own, and that doesn't include the release of Terminator 3: Rise of the Machines. Since James Cameron is returning, he's elected to ignore all the previous installments that he wasn't involved in and make the film a direct sequel to Terminator 2: Judgment Day (hence Linda Hamilton's involvement). And considering that the movie is a direct sequel to Terminator 2, Arnold Schwarzenegger has mentioned that it won't be titled Terminator 6. It will receive a subtitle just like all the previous sequels.
TIM MILLER IS DIRECTING TERMINATOR 6
Tim Miller marked his directorial debut with 2016's Deadpool, starring Ryan Reynolds. The film became an astounding critical and commercial success, which put him on Paramount's radar. And in 2017, he was hired to direct Terminator 6. News first broke of Miller's involvement in January 2017 along with news of James Cameron returning to produce, but it wasn't officially confirmed until September of that year.
JAMES CAMERON IS PRODUCING TERMINATOR 6
James Cameron made headlines in January 2017 when it was revealed that he would be returning to produce Terminator 6. Not only that but that he would also be rebooting the series with Tim Miller as director.
Cameron's interest in properly reviving Terminator is vested in making a Terminator movie that's relevant today. He previously said: "Is there anything to be said that I haven’t already said, and that would even be relevant in the 2020s (when these hypothetical films would come out)? I thought, ‘Well, let’s look at that.’" Cameron also wrote a story treatment for (which he submitted in September 2017) and is working with a handful of other writers to shape it into a full-fledged screenplay.
DAVID S. GOYER & JOSH FRIEDMAN ARE AMONG TERMINATOR 6'S WRITERS
When Tim Miller and James Cameron joined the project, Paramount commissioned a writer's room to shepherd the latest installment in the series (as they had done with the Transformers franchise for Transformers: The Last Knight). David S. Goyer (The Dark Knight), Justin Rhodes (Grassroots), Billy Ray (Captain Phillips), and Josh Friedman (Terminator: The Sarah Connor Chronicles) are all part of the writer's room that's being led by Cameron (who wrote the film's story treatment).
TERMINATOR 6 IS FIRST INSTALLMENT IN NEW TERMINATOR TRILOGY
Tim Miller and James Cameron are currently focused on making Terminator 6 the best sequel it can possibly be, but they're also laying the foundation for a potential continuation of the series should this first film achieve critical and commercial success. Cameron and the rest of the creative team are setting up stories for an additional two installments that will bring the entire series/story to a close; one last trilogy that "reinvents" the franchise. It's unclear when those extra sequels would release, though, especially considering Cameron's preoccupation with the Avatar sequels.