Sam Wilson and Steve Rogers are an iconic couple in the Marvel Cinematic Universe. From hunting down ex-assassins to battling titans from space, they continually follow each other into the line of fire. They fight by each other's side for what is right, time and time again.

Related: 10 People Steve Rogers Should Have Been With Other Than Peggy Carter

Sam is constantly by Steve's side, supporting him whenever he can. Steve returns the favor by showing the utmost respect for Sam and always taking his word to heart. The two never fail to prove themselves as a formidable team. Without Rogers and Wilson, the world would be a much darker place.

Sam Teaches Steve About Pop Culture

Steve and Sam first encounter, Steve's notebook in Captain America: The Winter Soldier

When Steve and Sam first meet, Steve explains the small journal of pop-culture references he keeps. Steve is about 70 years out of his comfort zone, so he has to learn about the new cultural shifts. Sam immediately has a suggestion for Steve: the Marvin Gaye Trouble Man soundtrack. This is Sam and Steve's first chance to bond, and Sam handles it very well. He doesn't fawn over Steve or laugh at his cultural illiteracy. Instead, he appreciates the idea and even tries to help Steve out.

Sam Gives Steve Advice At The VA

Sam and Steve talking in the VA in Captain America The Winter Soldier

Sam and Steve's secondconversation immediately takes a deeper turn. Sam reveals his backstory, although vaguely, which helps Steve to open up about his own doubts. It's clear that Steve feels comfortable around Sam despite barely knowing him. This is big for Steve, as he doesn't have a great track record when it comes to keeping friends.

Related: How It Started Vs. How It's Going For Sam Wilson In The Falcon And The Winter Soldier

Sam understands Steve in a way many others don't. Not only does Sam know how hard it is to shift from a military lifestyle, but he also understands what it's like to lose a brother in arms like Bucky. This meeting cements Steve Rogers and Sam Wilson as best friends with a future to become more.

Sam Takes In Fugitives Steve And Natasha

Sam Wilson giving his resume to Steve and Natasha in Captain America The Winter Soldier

At this point, Sam has met Steve only twice, but he immediately allows him and Natasha into his home despite their criminal status. He has learned a lot about Steve in their little time together, and he has almost no trouble trusting him. Sam doesn't know Natasha at all, but Steve trusts her, so Sam trusts her as well. This trust builds a strong foundation for Steve and Sam's relationship. Without it, Sam would never follow Steve into so many dangerous situations, and Steve would never trust Sam with his life.

Sam Doesn't Hesitate To Join Steve's Fight

Sam, Natasha, and Steve meet with Maria hill in Captain America: The Winter Soldier

Throughout Captain America: The Winter Soldier, the stakes continue to get higher, and the mission continues to become more dangerous. Despite this, Sam follows Steve into the line of fire without a second thought. When the plan is created to take down the helicarriers, Sam could have backed out and no one would have blamed him. He doesn't have super-human strength or specialized training like the rest of the group, but that doesn't matter to him. He has a moral standard that gives Steve a run for his money, and that's what makes them such a strong couple. This also, of course, leads to the reveal of Sam Wilson's iconic wings.

Steve Chooses Sam As An Avenger

Sam Wilson in winged superhero suit in Avengers: Age of Ultron

At the end of Avengers: Age of Ultron, the original Avengers choose more heroes to train up. After fighting Ultron, they realized there were bigger powers than they originally thought, and so more help was going to be necessary.  Steve's addition to the team is, of course, Sam. Sam isn't in this film much, but fans know he has spent the last year helping Steve look for Bucky. Steve knows Sam well at this point and recognizes the potential in him to become a great hero. Steve doesn't pass on this opportunity to help Sam become an even better man.

Sam Joins A Fugitive Steve (Again)

Sam and Steve meet at a bar in Captain America: Civil War

Captain America: Civil War sees Steve become a fugitive yet again. And, of course, Sam is right by his side the whole time. This time is different, however, because the government is after them. Hydra was an evil organization that everyone agreed needed to go. The government is different in that it isn't necessarily evil, and so many will support its decisions.

Related: Steve Rogers' 4 Most Heroic Moments (And 4 Of Sam Wilson's)

Sam had everything to lose by joining Steve, but he never thought he was making the wrong choice. Steve had never led Sam astray before, and he wasn't going to start now. Steve and Sam become a great team when they are forced to work outside the law.

Sam Helps Steve Find Bucky

Sam and Bucky at the airport fight in Captain America: Civil War

In Sam's eyes, Bucky is a murderer who has done nothing but cause Steve trouble for the last two years. But Sam knows how much Bucky means to Steve, and so he is willing to help find him. Steve's happiness is important to Sam. He understands what it's like to lose your best friend, and he wants to save Steve from further hurt. This is an important milestone for Steve Rogers and Sam Wilson because it enforces the trust they have in each other. Sam supports Steve in any way he can because he knows Steve would do the same for him. Bucky and Steve don't get along, especially at this point in time, but this doesn't stop Sam from being by Steve's side.

Steve And Sam Fight Tony's Team

Captain America and his team running toward battle in Civil War

Fighting the world's biggest billionaire and leading Avenger doesn't exactly sound like a good idea, but it's what Steve and Sam decide to do anyway. They're not only fighting for Bucky's freedom, but for their own. They lead the team together in a battle against Iron Man. Things don't go exactly as planned, and everyone except Steve and Bucky ends up in jail, but it helps Steve, and that's what matters. Even in jail, Sam refuses to give Steve up. Sam isn't exactly where he wants to be, but he trusts Steve and knows that he has done the right thing.

Sam's "On Your Left" In Endgame

Cap with his finger on his ear during the portals scene in Avengers Endgame

Sam and Steve's relationship began with the "on your left" quote, so it is only fitting that it returns during Steve's darkest hour in Avengers: Endgame. Steve knows there's no hope that he can stop Thanos with a full Infinity Gauntlet and army, but that won't prevent him from trying. Fortunately, he isn't left alone for long. Sam's line immediately fills both Steve and the audience with relief. In three words he is able to bring hope back to Steve, making this one of Sam Wilson's sweetest moments with Captain America. Even after being completely erased from existence, Sam can't leave Steve to fend for himself. He reappears at Steve's side, exactly where he belongs.

Steve Gives Sam The Shield

Steve Rogers gives Sam Wilson the Captain America shield in Avengers: Endgame

After everything Sam has done for Steve, it should hurt that Steve decides to go back in time. But Sam understands, as he always does, so Steve rewards him for his friendship. Steve knows Sam is a brave, righteous man, so who better to pass on the mantle of Captain America to? Steve has done all he can for the world, but he knows there is more in the world Sam can change. It is the biggest sign of trust and admiration that Steve so easily hands over the shield. Sam is hesitant to take it because to him no one can be Captain America except Steve. But Sam trusts Steve, and if Steve believes this is the right course of action, then Sam does too.

Next: 5 Times Captain America Followed The Rules (And 5 Times He Rebelled)