In the comics, Shuri takes up the Black Panther mantle.
There's a scene in Black Panther where Forest Whitaker's Zuri asks if anyone with royal blood is willing to challenge T'Challa for his seat on the throne. Shuri raises her hand to everyone's shock, but ends up just making a quick joke. The funny thing is though, in the comic books Shuri does take on the role of Black Panther for a while, as her brother deals with issues elsewhere. Letitia Wright, who plays Shuri in the billion dollar Marvel hit, recently visited the MCM Comic-Con show in London, and revealed that she would be down to take on the coveted role.
According to Deadline, Wright was asked what her character what do after the events that took place in Avengers: Infinity War. If you haven't seen the film, major spoilers are ahead. After Thanos completes his task of assembling all the Infinity Stones, he snaps his fingers and extinguishes half of life in the universe. Black Panther happens to be one of the characters that turns to dust in the wake of the "snap," so it would make sense for Shuri to wear the crown.
Wright answered the question about taking the throne carefully, "To be comic-book accurate, yes,” she replied. Obviously, Wright is under contract and cannot reveal anything that will happen in the future. It is worth noting though, that Black Panther director Ryan Coogler has expressed his yearning to create an all-female movie based in Wakanda.
Wright also spoke on the pressures of being a Disney princess. “I was like, ‘what’s this Disney Princess pressure? Do I have to be perfect?’,” she stated. “Then I realized that everyone’s just so geeked about having a different kind of female character in the Marvel universe and the Disney universe. And there’s going to be much, much more – I’m not the only Disney Princess to come to the surface and claim that title.” Wright continued on to say, “I’m so honored, seriously. I grew up on the Disney movies and grew up with the Disney Princesses and they didn’t really look like me. But now, you can go buy action figures and say ‘this is a Disney Princess’ – right on!”