While most games in the Kirby series are played in a 2D plane, there have been a couple to go 3D, such as Kirby 64's 3D graphics on a 2D plane, or Kirby's Air Ride which is actually a racing game. In fact, as far as I can recall there has never been a full-on 3D Kirby game where Kirby can roam around in 3D. That will all change next year when Nintendo releases Kirby and the Forgotten Land on the Nintendo Switch.
My first thought when looking at the trailer was kind of Kirby meets Super Mario Odyssey. The initial setting on the trailer shows an abandoned city though we don't see any humans walking around like SMO's New Donk City. We do get a glimpse of the gameplay as well as a few iconic transformations such as Sword, Cutter, and Needle. I'm always up for a new adventure with Kirby and I'll be keeping my eye on this one as it gets closer to release which sadly we'll have to wait until next autumn...or Spring. The trailer from the Nintendo Direct says Spring 2022 while a trailer posted to Nintendo's Facebook page yesterday says Autumn 2022. Again, I'll be keeping my eye out for any updates and hopefully we'll get the game sooner rather than later.