It will be a sub-set released in the wake of January’s S5I Single Strike Master and S5R Rapid Strike Master. The set will feature 70 cards (before secret rares), including Galarian Slowking V, Blaziken V, and apparently even more cards featuring Urshifu. The product description also mentions it will feature other Pokemon from The Crown Tundra.
The set name was previously revealed through trademark listings along with the names Silver Lance and Jet-Black Spirit, which seem to reference Calyrex’s new forms with Glastrier and Spectrier. Those sets would be releasing after this one, perhaps in April or May.
Yesterday we also learned of a new VSTAR trademark, which could also be an upcoming set name or TCG mechanic.
News of this March set also implies another major piece of news: Japan will not see a February set to celebrate Pokemon’s 25th anniversary. (Unless they release some kind of special product.) If anything, we will see one for the TCG’s 25th anniversary in the fall, like with Evolutions.
Thanks goes to Bangiras for the translations!