https://www.cnet.com/news/fortnite-brings-back-nfl-outfits-ahead-of-super-bowl-2019/

Fans of either the Patriots or Rams will also have the opportunity to duke it out in a limited-time mode called NFL Rumble LTM. This 20 vs. 20 match pits players in Rams uniforms against a rival team in Patriots garb to fight with unlimited respawns until one team is the victor. 

All of these football-themed items and game modes should be in play at least through the Super Bowl on Sunday, though Epic hasn't given us a date for when they'll go away. Like prior themed updates, they could be removed as soon as the weekly Fortnite patch next Tuesday.