The sixth expansion set in the Sword and Shield series will be called Chilling Reign and is inspired by the Crown Tundra DLC. It is scheduled for release on 18th June 2021.
The normal release schedule for expansion sets is February, May, August, November. Due to problems with demand exceeding supply Pokémon pushed back the release of Battle Styles from February to March. It would appear that the push back is being continued for Chilling Reign too and hopefully there will be no supply issues by then.
The new set is believed to have 190+ cards including 8 VMAX and 15 V cards. There will be V and VMAX cards of Shadow Rider Calyrex and Ice Rider Calyrex. Chilling Reign will continue the Single Strike and Rapid Strike style introduced in the Battle Styles expansion.
Chilling Reign will be available to purchase in Booster Packs and Booster Boxes, two elite trainer boxes and special collection boxes and tins. A Build and Battle Box will be available to purchase ahead of the launch date on 5th June 2021.