Despite being on-screen rivals, Iron Man actor Robert Downey Jr. helped convince Chris Evans to take his MCU role. Evans played Captain America in the MCU from 2011-2019.
Vanity Fair ran a story of alternate castings in the MCU. Turns out, Chadwick Boseman and Lupita Nyong'o auditioned for Guardians of the Galaxy roles prior to landing their Black Panther gigs. Another anecdote revealed was Downey's impact on Evans taking on the Captain America role.
Apparently Downey convinced Evans to pick up the Captain America shield as he thought it would make him a bigger star. Prior to the MCU, Chris Evans had starred in another superhero movie series, Fantastic Four. However, the role of Johnny Storm pales in comparison to Captain America — one of Marvel Comics' marquee characters.
Additionally, Marvel Studios also decreased the number of movies in Evans' deal. Typically, they like to lock in their actors for a lot of MCU appearances. For Evans, the number was brought down to six in an effort to further entice him. He'd end up playing the role in 11 total projects (in varying capacities) during his MCU tenure.
Outside of the MCU, Evans has also starred in Scott Pilgrim vs. the World (he'll reprise his role in the upcoming anime), Snowpiercer, Knives Out, and The Gray Man.
Robert Downey Jr. was the leading man for the MCU since Iron Man came out in 2008. He likely saw something in Evans that was perfect for the role. Thank goodness he managed to convince Evans to take on the role.