https://techcrunch.com/2018/07/20/niantic-explains-how-and-why-it-bans-players-in-pokemon-go/

Getting banned for cheating is nothing new in Pokémon GO. There’ve been big ol’ ban waves every few weeks for ages now.

The policies have never been totally set in stone, however — at least not publicly. Like many of the game’s mechanics, the player base has had to share info amongst themselves to figure out the offenses and their relative punishments, from slaps on the wrist to lifetime bans.