https://www.cnet.com/news/new-avengers-endgame-posters-from-marvel-reveal-shuris-unfortunate-fate/

The new posters show surviving characters in full color, with the dead featured in black and white. Most notably, Black Panther character Shuri (played by Letitia Wright) has a black and white poster. 

This kills the fan theory that Black Panther's sister would replace him, since he died in the Snap as well. Though fans who paid attention to the new Endgame trailers probably noticed when Bruce Banner looked at computer screens that showed characters missing and presumed dead from the Snap.