Well, it's pretty clear, if they're saying they will build "a greater world" with Phase 3, a mention of Wakanda would be entirely logical. Maybe Prince T'Challa appearing on a photo or something.
I mean, it's totally obvious Black Panther will be on Phase 3, they have Doctor Strange and Ant-Man confirmed, then who would be missing? He's the next major character Marve Studios has the rights to develop still not having a movie, plus he adds way much diversity and he's part of the current New Avengers brain-focused iluminati team, I think it's 100% safe to say Blackie will have his own movie
BUUUT. Still not sure about the actor. I'm still totally pro-Aldis Hodge.