League of Legends' Ahri, Evelynn, [relative newcomer] Kai'Sa and Akali blew up YouTube last week as Riot Games dropped the "POP/STARS" music video. Enamoring players and non-players alike, the video of course was an elaborate commercial for new skins. The response has been so overwhelming that Riot is altering a skin due to fan demand.
Akali's Twilight Shroud (which causes a smoke screen, hiding her and restoring energy) is being changed to fit more in line with her POP/STARS look. It's live on the PBE (public beta environment) now and will arrive in time for patch 8.23 later in the month.
As is customary with MOBAs, which can pretty much invent whatever lore they want due to their all-star-esque format, these skins are based in the "K/DA" universe: an alternate reality where pop music basically rules the world. Basically, it's the canon future for Bill & Ted's Excellent Adventure, just with pop instead of rock and the group K/DA instead of Wyld Stallyns.
The actual artists behind the video, Madison Beer, (G)-IDLE, and Jaira Burns, went on to achieve fame beyond the realm of League of Legends, as their single hit number one in the K-pop charts for Apple Music US and even managed to hit number four in pop.