It's just trailer music for the audience. I doubt Black Panther will be listening to rap in the movie
Besides, it's the MCU BP, so who knows what changes they made to the character and Wakanda.
They put Rap in both trailers, so it's safe to assume it'll be part of the soundtrack. It just makes little sense. It's an ill-fitting stereotype. As for the changes, they'll obviously downplay the fact that most Wakandas are *******s. And I mean real, ****ing *******s.