Klaue And Sokovia
Obviously, Black Panther features a fair few callbacks to Captain America: Civil War, as that’s the movie that saw King T’Challa make his MCU debut. However, there are also a few nods to an earlier film that sowed the seeds for the introduction of the character: 2015’s Avengers: Age of Ultron.
When T’Challa bumps into Everett Ross for the first time at the casino in Busan, South Korea, the CIA agent explains that they’ve been on Klaue’s tail since Sokovia. This refers to Ultron’s attack on the fictional European country. It seems the CIA were able to trace Ultron’s supply of Vibranium back to Klaue.
Speaking of which, the villain is armless in the movie, thanks to Ultron chopping his right hand off. In its place, he has a high tech sonic cannon made from Vibranium. This is very similar to his deadly artificial limb from the comics, though this one also comes disguised as a regular hand.