In Captain America: Brave New World, Adamantium is discovered in the Celestial Island, and is a key part of the worldwide treaty that Harrison Ford's Thaddeus Ross is championing. In a speech at The White House he says that the metal has numerous health properties and could be the most important discovery since Vibranium.

That's because Captain America: Brave New World brings adamantium into the fold. The substance shows up in the body of the Celestial that emerged from the Indian Ocean in Eternals. Now, it's the cause of international conflict, as major world powers try to control the world's only known adamantium supply.

Despite building up some anticipation for what’s to come, “Captain America: Brave New World’s” post-credits scene plays its cards close to the vest. The sole scene, which arrives after the full credits roll, sees Wilson visit Samuel Sterns (Tim Blake Nelson) at the Raft, a maximum-security prison for superpowered beings.