We already have the complete Pokémon Go expansion in Japanese!
The Japanese S10b expansion, also known as Pokémon Go x Pokémon TCG, is coming out soon. The release date will be June 17 in Japan and July 1 for the rest of the world.
This expansion will have different cards in Japanese as it happened in Celebrations. You can already pre-order it on the Pokemillon website by clicking on the Pokémon Go image.