Niantic has announce that they will build upon Trainer Battles, the current form of PvP battling that exists within Pokémon GO now and a new feature called the GO Battle League will be released in early 2020.

Coming 2020: GO Battle League

Trainers, Battling has been a core part of the Pokémon universe since the very beginning. We’re excited to announce the development of a feature that will build upon Trainer Battles, the current form of player vs. player battling that exists within Pokémon GO. This feature will be called GO Battle League.

Like many Pokémon GO features, GO Battle League will encourage players to get out and explore the world with Pokémon. Trainers will be able to walk in order to earn entry into the GO Battle League, then battle opponents from around the globe through an online matching system and rise in the ranks of the league. We hope this feature will make the Pokémon GO battling experience more competitive and accessible to more Trainers.

GO Battle League is slated for release in early 2020. We’ll be sharing more details in a special Dev Insights video soon. Stay tuned, Trainers!

Source: https://pokemongolive.com/post/gobattleleague-announcement