This article is from GameSpot
Update: Epic Games has now confirmed the surprise crossover with an announce trailer as part of Fortnite’s latest patch notes. Starting today until September 10, Fornite X Mayhem introduces a new Rift Zone based on the planet of Pandora, the setting for much of Borderlands’ looting, shooting, action. As well as adopting the Borderlands aesthetic, Pandora also includes an added bonus: go long enough without sustaining damage and a shield will automatically generate.
On top of this, the collaboration features new themed challenges that give you the chance to unlock some free Borderlands flavored rewards, such as a Mayhem wrap for your weapons and a Vault Hunter banner. The Psycho Bundle is now available to purchase in the store, too, letting you buy a package featuring a Psycho skin and Claptrap back bling. Meanwhile, new prefabs in Fornite Creative let you create your own Pandora.
Original story follows.
The Fortnite Twitter account posted a mysterious image that says, “When you see it…” The message used the hashtag #FortnitexMayhem.
This hashtag, combined with an image of a Psycho bandit from the Borderlands series makes it pretty clear this is in all in reference to some kind of crossover event between Fortnite and Borderlands. The most obvious possibility is that Borderlands skins are coming to Fortnite, but nothing is confirmed at this stage.
— Fortnite (@FortniteGame) August 27, 2019
Epic and Gearbox are already working together, as Gearbox is releasing Borderlands 3’s PC version on the Epic Games Store as a timed exclusive through April 2020. A promotional event for Borderlands 3 within Fortnite would likely be kicking off soon, as the game releases on September 13.
Fortnite has hosted numerous collaborations and crossover events, including one of its biggest ever when Thanos from the final Avengers movies appeared in the game with his own limited-time mode. Additionally, there was a Fortnite x Stranger Things crossover event as well.