Hard to decide.
Last gen (last decade) was about open worlds, online gaming, being, cover based shooting. I'd want a list defining this decade to feature 8th gen machines and what they brought to the table. Not my five favorite games but games that embody the last ten years.
-Fortnight: Free to play social gaming with tons of DLC and (I guess) loot boxes.
-Minecraft: Creativity and social aspects
-Super Mario Odyssey: Full featured home experience on the go.
-Hollow Knight: Indie games that are better than most big studio games
-No Man's Sky: Overhyped games that launch incomplete but become great later on
Wanted to mention a VR game too. Honorable mention to Astrobot, I guess.