Pokemon Co. is always doing interesting things with their animated features. It seems they're willing to experiment with all kinds of styles, and the latest animation is no different.
The latest cartoon shared by the company uses a style that echoes the golden era of animation. It pays tribute to classic cartoons from the Warner Bros./Disney/Max Fleischer/MGM era. The influences are totally obvious during this cartoon, and it's very clear the feature was made as a tribute to that era.