WARNING: The following article contains spoilers for Captain America #16 by Ta-Nehisi Coates, Bob Quinn, Matt Milla and VC's Joe Caramagna, on sale Wednesday, Nov. 20.
Steve Rogers may have willingly relinquished the title of Captain America in the Marvel Cinematic Universe, but for a time the title was stolen from him in the comics. The Secret Empire event series replaced Steve Rogers with "Hydra-Cap," an evil version of Captain America that pushed Hydra's evil agenda across the world.
Though Hydra-Cap was defeated, the public's trust in Captain America was ultimately tainted. Steve has tried his best to regain the public's faith in him, but the rise of the Power Elite has made the task very difficult. The shadow organization framed Steve for the murder of Thunderbolt Ross, resulting in the hero being sent to a supervillain prison. Luckily, Sharon Carter and the Daughters of Liberty (Spider-Woman, Invisible Woman, Mockingbird, Echo, Misty Knight, White Tiger and Annabelle Riggs, the former human host of Valkyrie) are able to free Steve, turning him into a man on the run while also attempting to bring down the Power Elite.
This has led the group to investigate the reappearance of the Scourge, who just murdered a group of New York police officers. So far, all leads have turned up empty, except for an old arsenal cache uncovered by Misty Knight in a preview of Captain America #16. While it doesn't look like Scourge has been there, it is obvious that someone has recently visited the safehouse.
Just as Misty is about to relay some information to Steve, she's attacked by an unknown assailant. Captain America hustles to provide backup, but once Steve arrives he's attacked from behind by John Walker, the U.S. Agent.
Diehard comic book fans may already be familiar with U.S. Agent, but soon subscribers of Disney+ will be introduced to the character when Wyatt Russell portrays him in The Falcon and The Winter Soldier. U.S. Agent is another patriotic hero in the mold of Captain America, who is also armed with a red-and-black shield. He has danced between hero and antihero on many different occasions, and it remains to be seen how U.S. Agent will be depicted in the MCU when The Falcon and The Winter Soldier debuts in Fall 2020.
The most likely scenario for U.S. Agent's attack on Steve Rogers in the Captain America #16 preview is the government either ordered U.S. Agent to bring Cap in, or he has taken it upon himself to do the deed. As you can see, John Walker feels betrayed by Steve Rogers, meaning he believes Cap is guilty of the crimes he is charged with.
The timing of U.S. Agent's appearance couldn't be timed any better, especially after new concept art of Captain America's successor was unveiled in the Disney+ special, Marvel Studios: Expanding the Universe.