https://www.gamespot.com/articles/fortnite-playground-ltm-is-now-live-these-changes/1100-6460711/

Fortnite's Playground mode is coming back to the battle royale game on July 25, and now developer Epic Games has detailed everything that's new since we last saw it. [Update: The limited-time mode is now live in-game across PS4, Xbox One, PC, Nintendo Switch, and mobile. Read on for a look at how it differs from the previous instance of the LTM.]

There are lots and lots of changes, one of which is that players can now switch teams mid-game. The idea is that you can swap sides to work together with friends on strategies and then switch to hone your fighting skills. Voice chat is on for all teams, but Epic plans to add "more customisation" options in the future.