Apple has demonstrated, at minimum, that its appeal raises serious questions on the merits of the district court’s determination that Epic Games, Inc. failed to show Apple’s conduct violated any antitrust laws but did show that the same conduct violated California’s Unfair Competition Law. See City of San Jose v. Off. of the Com’r of Baseball, 776 F.3d 686, 691–92 (9th Cir. 2015) (“[U]nder California law ‘[i]f the same conduct is alleged to be both an antitrust violation and an “unfair” business act or practice for the same reason—because it unreasonably restrains competition and harms consumers—the determination that the conduct is not an unreasonable restraint of trade necessarily implies that the conduct is not “unfair” toward consumers.’” (quoting Chavez v. Whirlpool Corp., 113 Cal. Rptr. 2d 175, 184 (Cal. Ct. App. 2001))).
In other words, if the appeals court agrees with the district court that federal antitrust laws were not violated (which is very likely) then they're going to overturn the UCL judgement as well.