This case boils down to how much money everyone makes when someone buys V-bucks in Fortnite.
It might be hard to remember, but there used to be a time when iPhone users could play Fortnite. That changed back in 2020 when Epic Games antagonized Apple by skipping the App Store billing system. Apple pulled the game, and the companies have been battling it out in court ever since. Apple came out on top in the case, with Epic winning on just one argument. Apple only accepts total victory, though, and has continued the fight. Unsatisfied with the Appeals Court, Apple just requested a hearing at the US Supreme Court to decide the matter once and for all.
This case boils down to how much money everyone makes when someone buys V-bucks in Fortnite. Apple requires that all iOS apps use its App Store and purchase mechanisms, which charge a 30% fee for each sale. Epic challenged the very nature of the App Store, contending that iPhone owners should be permitted to get apps from third-party repositories without hacking their phones.
