https://www.polygon.com/2017/12/7/16748276/fortnite-battle-royale-50-vs-50-trailer-date-tga-2017

Epic Games has announced a brand new 50-versus-50-player game mode for Fortnite: Battle Royale. The free mode will appear as a new playlist inside the unified Fortnite client on Mac, PlayStation 4, Windows PC and Xbox One. It will only be available for a limited time, from Dec. 8 to through Dec. 17.

The new game mode will allow players to form squads with up to four of their friends, and then merge them into a random team of 50 players. Everyone on your side will appear in-game with a green chevron over their heads. Friendly fire will be turned off, and players will be able to offer aid to those on their side who have been downed but not finished off. The game will proceed until one entire side has been eliminated.