Since Jeremy Renner was meant to take over the mantle of the Bourne movie franchise, when Matt Damon decided he wanted to return, things changed in a big way. It’s been made clear, however, that there are still plans for Renner in the Bourne universe. This leads fans to wonder if the two characters will ever cross paths. If that decision is ever made, you can count Aaron Cross in.
Speaking with ScreenRant as part of the promotion tour for Mission:Impossible-Rogue Nation Renner said that he loves the Bourne franchise and would be interested in working with (or against) Damon if the studio ever makes that call:
Yeah, I mean in two seconds. I love that world. I love the character. If they want to do that, I’m in. there’s no ‘no’ coming from this direction.
It’s hard to imagine that there would be a "no" coming from any direction but you never know. While The Bourne Legacy was not the huge smash that the previous films had been, it put up respectable box office numbers. In addition, Renner has become a much hotter property since then, what with the Avengers and the Mission:Impossible. Fans of the Bourne franchise will be glad to know Renner is interested in the crossover, he has "cinematic universe" experience after all. However, Renner points out that he has no decision-making power within the franchise. There are many more people who need to get on board first.
While the producer behind the Bourne films, Frank Marshall, has been pretty clear that Renner and Aaron Cross are not being dumped now that Damon’s Jason Bourne is back in the mix, he’s also been clear that the two characters are being kept separate. While there are still plans for a direct sequel to The Bourne Legacy those plans have put on the back burner ever since Damon and his Bourne director, Paul Greengrass, came back to the fold. There's now no timeline for when the film will happen. While the idea of a crossover has not been rejected out of hand, the producers have made no direct statements that such a thing is even being actively considered.
At some point, somebody will ask Matt Damon what he thinks. If Damon is on board then you can expect wheels to turn a little faster. He certainly has power over the franchise. Of course, if he doesn’t want to do it, that will kill the idea dead. There certainly won’t be any crossover until after Renner’s solo Bourne return which is still planned to happen sometime after the director is done with Star Trek:Beyond.