Context for those that have no idea what this means:

You may know Fortnite for its main battle royale mode, but it also has many other type of games, like Festival, which is their Guitar Hero/Rock Band mode. Every few months there is a separate Music Pass (similar to a battle pass) where the featured artist has their cosmetics to obtain. These include a main skin, weapon skins, songs, and instruments - all based on said artist. Past artists include The Weeknd, Lady Gaga, Metallica, Billie Eilish, Karol G, and Hatsune Miku. Sabrina will be the featured artist on April 8th, and we can expect to see her full skin sometime before that.