Matt Damon will reprise as Jason Bourne in the upcoming fifth Bourne movie installment (currently referred to as Bourne 5), with Bourne Supremacy/Ultimatum helmsman Paul Greengrass back in the director's chair. There are tentative plans for Jeremy Renner to play Bourne Legacy protagonist Aaron Cross again in an upcoming Bourne film, but as of right now Damon and Greengrass' project is the only one based in the Bourne universe that's actively moving forward.
Principal photography on Bourne 5 should be getting underway as soon as next month (July, at the time of writing this), in order to make its scheduled Summer 2016 release date. It's been reported that Alicia Vikander (Ex Machina) is circling a key role in the film alongside Damon, and now we have word about two other prospective cast additions - one who is a veteran of the Bourne franchise, the other a newcomer.
Variety is reporting that Julia Stiles is set to costar in Bourne 5, reprising her role as (ex-)CIA agent Nicky Parson from the first three Bourne movies. Additionally, Variety's sources are saying that Vikander remains in talks for project, while Viggo Mortensen is apparently holding the offer to play an assassin who tracks Jason Bourne in the film. However, the site warns that it's not clear yet if Mortensen is leaning towards joining the movie's cast or not.
Mortensen has mostly stuck to indie and/or arthouse fare since his days appearing in the Lord of the Rings trilogy (including, multiple David Cronenberg films). Damon's Bourne movies are held in higher critical regard than similar assassin action/thrillers, though, and the return of Greengrass as director would no doubt help to further convince Mortensen to join the Bourne 5 cast. He almost took a role in Quentin Tarantino's upcoming western The Hateful Eight before passing due to scheduling issues, but the actor should be available in this case... assuming he wants the role in question, anyway.
Stiles' Agent Parson serves as one of the links connecting the original three Jason Bourne movies, so it only makes sense for her to continue playing a role in the next chapter. Nicky's knowledge of Bourne's psychological issues would presumably come into play during the Bourne 5 narrative - as featured in the script that Greengrass and Damon have written alongside Christopher Rouse (Greengrass' longtime editor). The character also alluded to her shared past with Jason in Bourne Ultimatum, so it's possible that this new chapter will delver further into their history together, too.
Universal Pictures, like every other major Hollywood studio right now, has shown an interest in further franchising the Bourne series beyond one more film with Damon and Greengrass. Marshall has likewise indicated that either a direct sequel to Bourne Legacy and/or a Bourne film installment featuring both Damon and Renner could happen in the future after Bourne 5. However, for the time being, we're just waiting to see if Bourne 5 makes for a worthwhile addition to the franchise - and avoids coming off as unnecessary, following the conclusion to Jason Bourne's story provided by Bourne Ultimatum.
Bourne 5 opens in U.S. theaters on July 29th, 2016.