There's a "Black Panther" Easter egg that connects it to "Doctor Strange"
Marvel’s latest film, Black Panther, very much operates as a stand-alone film. There are certainly references to events that came directly before it in Captain America: Civil War — and how T’Challa inherits the throne in Wakanda. But aside from that and Bucky Barnes showing up at the very, very end of the movie, there aren’t any other references to the greater Marvel Cinematic Universe. But there is a tiny, subtle reference to the MCU, specifically Doctor Strange.
It might seem odd that out of all the other Marvel movies, Stephen Strange would get roped into the turmoil in Wakanda, but the Sorcerer Supreme is referenced by none other than Michael B. Jordan’s Erik, aka Killmonger, during his plot to take over Wakanda, and eventually, the world.
If you remember, Doctor Strange takes place in New York City, which is very far away from Wankanda. Strange lives in the Sanctum Sanctorum there, which Thor also happens to visit during Ragnarok. However, this is not the only Sanctum Sanctorum, as there are two others: One in London, and one in Hong Kong.
In Black Panther, after Erik takes the throne in Wakanda, he explains that he’s going to send the nation’s technology and weaponry all over the world to help those who are oppressed. Wakanda has spies all over the world, who will fight against whatever Erik is planning…except for the Wakanda spies in three locations who seem to agree with Erik’s plan to rule. Those locations where Erik has allies? New York, London, and Hong Kong.
Since there’s no such thing as a coincidence in a Marvel movie, there is most definitely a reason behind Erik naming these three locations, which are also the three locations directly connected to Doctor Strange. Are the Wakanda spies living there watching the Sanctum Sanctorums? (However, don’t forget, the London Sanctum Sanctorum was destroyed.) Are they the ones that set off ~whatever~ happens at the beginning of Infinity War that paves way for Thanos?
As we’ve already seen in trailers for Avengers: Infinity War, the movie is going to take us back to the remaining Sanctum Sanctorums, and also Wakanda. Even though Erik might be gone, it still sounds like his world domination plots might still be in play.