While MCU. From the moment they meet and decide they don’t like each other, they have a rocky relationship, although, at times, they consider each other a close friend.
This relationship leads to many of the conflicts in the franchise, including the central one in Captain America: Civil War, with plenty of key moments in between, all the way up to Avengers: Endgame.
Their Antagonistic Meeting
When Steve and Tony meet for the first time aboard the helicarrier, they already hold preconceived notions about each other. Tony feels resentment over the way his father, Howard, compared him to Steve, and Steve assumes that Tony is selfish and unwilling to make hard sacrifices.
The tension between them makes for a compelling dynamic right off the bat, and while they don’t like each other, they do have good chemistry that fans enjoyed watching.
Working Together & Forming The Avengers
The first Avengers film is all about the Avengers learning to work together as a team, so while it’s not just Steve and Tony, they have to learn to be co-leaders of this new group.
Throughout the movie, they grow to rely on each other more, and Steve even learns that Tony is willing to do the “sacrifice play.” There’s newfound respect between them, but it’s still a rather shallow one that will soon be broken.
Tony Building Ultron
While Tony and Steve were acting like steamers at the start of Avengers: Age of Ultron, and fans especially loved seeing all of the heroes together at the party, this didn’t last long.
Tony created Ultron, and Steve, as well as many of the others, were upset about his lack of oversight and recklessness, and there's a reason it's considered one of the worst things Tony ever did. This once again put a rift between them as Steve was frustrated at Tony’s arrogance, and they went through similar pain in this movie as they did in Avengers.
Tony Builds The Avengers Compound
When Age of Ultron ended, Steve and Tony were back to being friends. One of the last scenes included them walking, along with Thor, and they were all bantering with one another. Tony had even built the upstate compound which gave Steve and other heroes a place to train and helped Steve further his leadership position.
Tony building this new home was one of his most generous acts, but, once again, this peace and companionship between the two didn’t last very long. Likely because these characters were more interesting as rivals than as best friends.
They Disagree On The Accords
While the Captain America: Civil War movie is Steve’s solo film, it revolved heavily around Iron Man, too. The conflict put them at odds on both an ideological level as well as a more personal one.
But, their hurt toward one another did reveal that they cared for the other person. Steve felt upset that Tony hadn’t talked to him about the Accords in private, and Tony felt betrayed by Steve keeping secrets from him, too.
The Fight With Bucky In Siberia
The fight between Steve, Tony, and Bucky in Siberia is what really ripped the relationship between the two, and the Avengers as a whole, apart. Steve had to protect Bucky in the name of their friendship, but Tony also understandably was devastated knowing Steve hadn’t told him the truth about his parents.
While this fight had far-reaching implications, it did also feel like two people with a complicated relationship who felt betrayed by the other.
Steve Leaves A Cell Phone With Tony
While the friendship between Steve and Tony seemed nearly severed for good at the end of Civil War, a line of communication was left open. Steve left an old flip phone with Tony saying he would call him if needed.
Of course, this letter and phone didn’t fix anything between them at all, but it did point to the fact that this relationship would have to be amended at some point. Fans just wanted to see how it would happen.
Tony Returns To Earth In Endgame
While many viewers were hoping Captain America and Iron Man would work together in Infinity War, they spent the entire movie on different parts of the universe. This meant that it wasn’t until Avengers: Endgame when they saw one another again.
Tony was deeply angry at Steve after everything that transpired between them, and their interaction felt personal and almost like a lover's quarrel. Then, it appears as if they didn’t really speak again for years.
They Go Back In Time Together
Five years after the Blip, Steve and the other Avengers asked for Tony's help. In some ways, Tony distancing himself so much from the Avengers is upsetting because his characterization before involved him being attached to the team as his family.
Overall, this made him feel out of character. However, fans were still mostly happy when these two teamed up and set aside their differences and past hurts to go to the past to get the Pym Particles.
Tony’s Death & Steve’s Departure
While the reunion and making up between these two characters could have been more developed and satisfying for fans, it did at least happen somewhat. They were on decent when Tony died to save the universe.
Sadly, audiences weren’t really shown how that loss impacted Steve as his only scene after going back in time to be with Peggy involved only Falcon, and arguably left many of his other relationships unresolved.
