The Two Professors

The Two Professors is a series of three CGI-animated shorts prior to the release of Pokémon: Let's Go, Pikachu! and Let's Go, Eevee! featuring Professor Oak and Professor Willow and the Mythical Pokémon Meltan. The episodes were uploaded to the official Pokémon YouTube channel beginning on September 25, 2018.

(Source: Bulbapedia)