I wasn't able to retrieve the actual content of this article — the page returned only a JavaScript/cookie verification message rather than any article text, so no details about the Pokémon Pokopia Expansion Pass trailer are available to summarise.

Based on the title alone, this appears to be a GameSpot video showing an extended overview trailer for an expansion pass related to a game called "Pokémon Pokopia." No further details, release dates, features or context can be confirmed without access to the actual video or article content.