https://www.pcgamer.com/fortnites-playground-mode-returns-on-wednesday/

Epic revealed on Twitter today that Fortnite's Playground limited-time mode will return on July 25, with new team select options, all-terrain karts, and more loot to earn. 

No specifics at this point, but Epic said earlier this month that it wanted the return of the Playground to include team selection options to enable 1v1 and 2v2 games, teammate structure editing and trap reactivity, the ability to clock enemies with the pickaxe, and other play-with-pals features. Full details will be revealed in the 5.10 update notes, which will drop early tomorrow morning—and which will also finally deliver those fancy Founder's skins everyone's been waiting for.