Epic Games has been cross-promoting content between Fortnite and Rocket League for some time now. It initially started off small, but over time, things have become bigger.
Rocket League Codes for January 2024
Fortnite players demand Epic Games adds Battle Pass feature from Halo Infinite - Dexerto
Rocket League' on Switch Comes with Exclusive Nintendo Battle Cars
Epic is thinking about adding these cars to Rocket Racing (Via: @Loolo_WRLD - @xboxera & @thgamerhub) : r/FortniteLeaks
Rocket League Devs Reassures Worried Players After Rocket Racing Releases
Fortnite leaks suggest Car Hijacking is currently in development
ROCKET LEAGUE VEHICLE! - Fortnite Creative Update
Fortnite leak suggests Rocket League vehicles could be added in soon
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Fortnite leak shows another Rocket League collaboration
Fortnite leaks suggest open-world game mode to feature different biomes, wildlife, NPCs, and more
Fortnite Rocket Racing: release date, cars, tracks, and Rocket League crossover explained - Mirror Online
Rocket League x Fortnite cross game progression details : r/RocketLeague
All Leaked Cars for Fortnite Rocket Racing so far (Via @beastfncreative, @NotJulesDev, and @SamLeakss) : r/FortniteLeaks
Fortnite Rocket League Racing Mode Release Date Revealed