I don't know if it's because people already assumed he would be back or just nobody really cared enough to find out, but without much fanfare Jeremy Renner has revealed that he will indeed be back for Mission: Impossible 5 – in an interview with Yahoo from several days back, to boot.
The answer comes from when the interviewer asks if he'd consider starring on True Detective season 2, because I think this is the new question that you must ask every celebrity you come across:
It's kind of unlikely. In fact, I'm kind of strapped time-wise doing Avengers 2, and Mission: Impossible 5 is rearing its head, and then they want to do another Bourne movie. It's unlikely I can find the time right now.
Renner played Tom Cruise's Ethan Hunt's fellow agent William Brandt, and when he got cast, there was this plan in place that he and his character would actually take over the franchise from Cruise at some point, when he truly and finally got too old to be an action star. Well, clearly he has at least one more in him, so Renner and Brandt will still be supporting players this time around.
But maybe Mission: Impossible 6 will finally be his time.