John Walker
US government made John Waler the next Captain America after Steve resigned from his title due to a revulsion for US government for its corrupt nature. Walker goes on a killing spree without any qualms. After being confronted by Steve Rogers for his ways of killing, Walker returned the costume and shield. It was later that Walker took on the name of Raft, becoming the warden of superhero prison.
Scott Summers
Popularly known as Cyclops, a member of X-Men team. It is said, in an alternate universe of Earth in 81122. A supposed accident leaves Scott, Jean and Steve robbed of their powers. Due to the rapid aging of Steve Rogers, Scott takes on the title of Captain America. During his role as Captain America, we can see him with X-men head on with Sue Storm and the fantastic four.
Sam Wilson
Falcon is known to take over the title of Captain America of recently. With the decaying of Super Soldier Serum blood, Steve starts ageing rapidly, passing his shield onto Sam Wilson.
During his tenure, Wilson fought against Red Skull and Hydra, while leading the Avengers.
