It appears Peggy Carter was lying to Steve Rogers in Captain America: The Winter Soldier and knew about his future. Peggy and Steve's time together was cut short during World War II after Steve crashed Red Skull's ship, but that wasn't the end of their story. They were reunited after Steve was unfrozen, but only for a short while before Peggy passed of old age. However, Avengers: Endgame concluded with the reveal that Steve went back in time to live a full life with Peggy.
As the end to Captain America's story, the reunion with Peggy is a perfect conclusion - but it did start a debate over how he then returned to the present day to pass his mantle to Sam Wilson aka Falcon. The Russo brothers explained that Steve lived out this life with Peggy in an alternate reality, but Avengers: Endgame's writers Christopher Markus and Stephen McFeely said otherwise. Their rationale is that the main MCU continuity has always had an older Steve in the shadows. As the writers most responsible for Steve's MCU journey, they say they've had the idea of Steve returning to live with Peggy in mind for a while. But if this is true, then that means Peggy is lying to Steve in The Winter Soldier.
In the sequel, Steve visits an aged and sick Peggy, who now appears to have lied to Steve as she knew of his ultimate future. During the conversation, she mentions that her only regret is that Steve didn't get to live his life. This is the lie, as Peggy knows that Steve will live a full life with her one day. She goes on to say, "The world has changed and none of us can go back. All we can do is our best and sometimes the best we can do is to start over." This conversation plays completely differently after Endgame and Markus and McFeely's explanation of Cap's journey.
The confirmation that Steve did become Peggy's husband may not have come until Endgame, but this scene in The Winter Soldier is where the set up first occurred. The movie made sure not to show any picture of Peggy with her husband. Furthermore, an archived interview with Peggy from 1958 included her saying that Steve saved the man who would become her husband back in WWII. She even mentioned that "even after he died, Steve was still changing my life." The revelation that he didn't actually die definitely falls under the life-changing category, especially since they got married.
Even if this ending was locked in stone back when The Winter Soldier was made, there's no other option for Peggy than to lie to Steve about his future. She couldn't tell him what would happen over the next decade or so of his life, as doing so could have likely altered Steve's mindset and decisions he made. The best Peggy could've done is maybe give him some advice about not pursuing a relationship with a nurse down the hall, just so nothing happened between him and his great-niece.
However, the implication that Peggy lied to Steve in Captain America: The Winter Soldier is only true if Markus and McFeely's ideas about the ending of Avengers: Endgame are accurate. We already know not everyone involved with the movie feels the same way, but neither explanation has been explicitly made canon so far. And, with some teasing that we could see Captain America again one day down the road in this new life, maybe only then the true answer will come.
- Black Widow (2020) release date: May 01, 2020
- Shang-Chi and the Legend of the Ten Rings (2021) release date: Feb 12, 2021
- Eternals (2020) release date: Nov 06, 2020
- Doctor Strange in the Multiverse of Madness (2021) release date: May 07, 2021
- Spider-Man: Homecoming 3 (2021) release date: Jul 16, 2021
- Thor: Love and Thunder (2021) release date: Nov 05, 2021
- Black Panther 2 (2022) release date: May 06, 2022