Steve Rogers, original Captain America, retired as the Avengers captain at the end of the Endgame: Endgame at the end of 2019. He also handed over his armor to Sam, basically declaring him his successor.
It is unknown at this time what he will do after leaving the post. He and Wilson teamed up with the anarchist group Flag-Smashers in The Falcon and Winter Soldier. The decorated soldier John Walker briefly became Captain America, but was fired from that role after he killed one of the flag-smashers with cold blood.
Maybe Marvel wants to continue their bond and develop further.
Mackie He first played the role of a falcon in Captain America: The Winter Soldier. He is a veteran who runs a self-help group for soldiers suffering from post-traumatic stress disorder. He attached the cap and removed the hydra, which not only escaped but also penetrated the shield.
Captain America: During the Civil War, he once again sided with Steve Rogers against conflict with Iron Man and his allies. After the movie events, he escapes and joins the battle against Thanos.
Sam was also among those who disappeared after the Thanos snap. In the endgame, he fought the Mad Titan and his forces against the other Avengers.