The CIA is in the MCU too. they focus on fighting an organization called Hydra. And Lee Harvey Oswald is a Hydra handler, and his agent is The Asset, known to the members of the intelligence community who believe he exist as the Winter Soldier. Lee Harvey Oswald didn’t actually assassinate John F. Kennedy, he was just covering for the Asset. He allowed himself to get caught, and he was killed by a Hydra agent as he was being brought to an armored car that would take him to the courthouse. The agent was named Jack Ruby. You see, Hydra knew that they could not trust Oswald to keep his mouth shut so they sent an agent that could keep his lips sealed to kill Oswald and (probably) get arrested. That way, the secret of The Asset would be kept safe for many more decades, until on one mission, Hydra sent the Asset to retrieve an agent. This should have been an easy task: Grab the agent kill the people in the car, and leave. What Hydra did not consider though, was that The Asset had known one of the people in that car. His name was Steve Rogers. Hydra did not expect was that Steve would recognize The Asset. Hydra had no idea that The Asset’s mask would fall off. They had no idea that something as simple as calling The Asset by his name, not the Winter Soldier, or The Asset, but his REAL name, would trigger his memories of his past life. And this time, wiping him wouldn’t fix the problem. The Asset managed to hold onto that name, and that face, despite having his mind wiped. And that was how Hydra lost The Asset. Because after decades of brainwashing and torture, the Asset remembered.
[Sorry this is long. I was bored in history class so I typed up some avengers stuff.]