A crossover between Fall Guys and Fortnite is seemingly in the works.
As reported by Fortnite insider iFireMonkey, Epic was previously found working on adding URLs that redirect to the Fall Guys website, implying that some sort of content was coming to Fortnite that would link to Fall Guys. That was already a pretty good sign that something was in the works, but iFireMonkey is now reporting that those URLs have been updated to read, "epic.fall.guys.competition".
This has caused some to speculate that crossover Trial Events are on the way, similar to the Lantern Trials that were previously shown off on the Fortnite website. Interestingly, iFireMonkey also pointed out that a crossover between Fortnite and Fall Guys has seemingly been in the works for the past year, as leaks dating all the way back to November referenced Fall Guys costumes and nameplates.
Some of the content that was leaked back then included Peely, Bunny Brawler, Cuddle Team Leader, and Llama outfits making their way to Fall Guys, as well as nameplates like "Loot Llama", Slurp", and "Battle Bus". The leaked content seems to be for Fall Guys instead of Fortnite, as Fortnite doesn't have nameplates and the costumes are all Fortnite characters, so it'll be interesting to see what comes to Fortnite for the crossover.
From how long ago the crossover was leaked, it seems that Fortnite and Fall Guys crossing over has been in the works for some time, but the recent change to the URL on the Fortnite website makes it clear that it's close to actually happening. To back this up further, FNLeaksAndInfo reports that Mediatonic has recently added support for cross-game items similar to how Rocket League does it so that completing a challenge in one game will unlock content for a different one, which could be what happens here.
It's not clear how extensive the crossover might be, but at the very least we know that something is in the works between the two games and that something will be happening in the near future.