The cars were rolled out to Fortnite in Season 3 of Chapter 2, and since then players are still hoping that Epic Games will do more with these new vehicles.
This may be expected since datamineur Mang0e found "AI generation capabilities for vehicles" in the game files. These have not yet been published but were added in the 15.40 update dated February 16th.
While we don't have any details yet, the leaker imagines that NPCs could be driving these cars on the island of Fortnite - making the map much more dynamic.
Another possibility, these vehicles would be full-fledged bosses, which would have to be eliminated via weekly challenges such as Wolverine or, more recently, Predator.
Keep in mind that this is just speculation at the moment, and it is not impossible that Epic Games will decide to simply remove or not use these codes.
Earlier this year, HYPEX also suggested that mods for these same vehicles could see the light of day. He then specified that these accessories would be divided into several categories, each with different effects. This system could also happen for in-game weapons, which would grant them unique abilities.
Knowing that Season 5 is scheduled to end around March 16 , it is much more likely that these new features will appear when season 6 rolls out.
We could see a collaboration with a license like Fast & Furious, with the ninth film scheduled for release on May 26, 2021.