Cutting it a bit fine, the Pokémon Company have announced that they will reveal news on Pokémon Sword Shield Crown Tundra Expansion Pass on September 29. A livestream will air at 6am PDT (9am PDT/ 3pm CEST) on the day that will shed light on the second part of the Expansion Pass. Hopefully, we should get a date as to when it will become available.
The livestream can be watched via the embedded video below. Alternatively, you can use this link to go to the livestream on YouTube.
Source: Pokémon Company (Twitter)