Enter Henry Cavill as August Walker, who was initially presented in Mission: Impossible – Fallout as an operative working for new CIA Director Erika Sloane, but later revealed to be John Lark, the criminal Ethan Hunt and his team were tracking who hired The Apostles to find Solomon Lane, the main antagonist from Rogue Nation. Shortly after it was revealed that August was Lark, he killed Alan Hunley while escaping custody. By the end of Fallout, though, Walker met his demise at Ethan’s hands.
Article source: https://www.cinemablend.com/news/2465438/the-next-mission-impossible-movies-could-bring-back-two-surprising-characters