https://www.gamespot.com/articles/fortnite-week-7-road-trip-how-to-get-free-secret-b/1100-6461394/

Fortnite's Week 7 challenges on PS4, Xbox One, PC, Nintendo Switch, and mobile, bringing the running tally of Season 5 challenges to a whopping 49. As usual, completing these will level your Battle Pass up and unlock Season 5 rewards, but there's an extra incentive to finish all of the challenges in a given week; doing so will check off a corresponding Road Trip challenge and net you a special loading screen that points to a secret Battle Star hidden around the island.

If you've managed to stay on top of all of the challenges to date and clear Week 7's batch of tasks, you'll unlock the loading screen pictured below. This one depicts a group of characters standing around in shock as another group--dressed in the Legendary Enforcer outfit you receive for completing seven Road Trip challenges--emerges from a Rift atop the motel sign.