Kaldheim is a tribal set, with Humans, Giants, Elves, Dwarves, and shapeshifters. In lieu of the abandoned block model, R&D has found a new way to tie together the three non-core premier sets in a single Magic "year" (aka the fall, winter, and spring sets—using northern hemisphere seasons): they share a common mechanic.
Changeling is a returning keyword ability that gives a creature or creature card all creature types, no matter where it is. Glory Awaits. And those, my friends, are the mechanics of Kaldheim. But there's so much more to this set!