https://www.cnet.com/news/detective-pikachu-and-other-pokemon-playmojis-now-available-in-playground/

Playground uses ARCore's motion tracking to better understand the real world and light. This will make it look like the Pokemon are really there in front of you.

"You can even take a selfie with Detective Pikachu and share a smile as he reacts to your facial expressions in real time via machine learning," Google said.