https://www.pcgamer.com/fortnite-celebrates-its-first-anniversary-with-a-limited-time-birthday-event/

Fortnite Battle Royale went live in late September 2017, but Fortnite as it was originally conceived—a base-building zombie defense game, kind of a mashup of Minecraft and Left 4 Dead—came out on July 25. That means that the first anniversary is less than one week away, and Epic isn't letting the birthday pass without a party. 

A limited-time event celebrating the big day will kick off on July 24, giving players the opportunity to earn special cosmetic items by completing birthday-themed challenges and quests. Dealing 1000 damage to opponents will unlock the Fortnite Birthday! emoticon, dancing in front of ten different birthday cakes will get you the Happy Birthday! spray, and playing 14 matches will earn you 5000 XP. Complete all three challenges and you'll also get the Birthday Cake Back Bling.