Avengers: Endgame - 10 Behind-The-Scenes Photos You Must See

7. Vibranium

Just hanging out, chatting about vibranium. pic.twitter.com/ryzEcVlOJS

— Chris Evans (@ChrisEvans) May 5, 2019

It's clear Captain America and Black Panther have developed a strong bond: T'Challa shielded Bucky from the U.S. and answered Cap's call to action in Infinity War, plus he was the first dusted superhero to walk out of the portals to assist Cap on the battlefield in Endgame.

And now we know the reason for their bond: vibranium. You know, that metal that Cap's shield and Black Panther's suit are made out of.