https://www.gamespot.com/articles/fortnite-free-battle-pass-tier-available-for-compl/1100-6458994/

Week 3 of Season 4 is well underway in Fortnite: Battle Royale, which means a new set of challenges are now available for Battle Pass holders. As usual, the challenges present a mixture of objectives to complete that allow you to level up your Battle Pass and unlock new rewards, but there's another bonus waiting for players who manage to clear them all.

As has been the case the past two weeks, players who clear all of the challenges in a given week will complete one of the game's new Blockbuster challenges. The reward for doing so is a special loading screen; while primarily cosmetic, the real value in the loading screen is that it hides a secret that leads to a free Battle Pass tier.