The Guardian Medivh set that briefly appeared in the Trading Post has now been added to the in-game store.

For a limited time, you can purchase The Guardian Pack for $8. It will leave the shop on May 31, 2023. The set will also be available in a future rotation of the Trading Post, but no sooner than 3 months after it leaves the shop, according to Blizzard.

(Source)

An homage to the Last Guardian

Shroud yourself in an aura of mystery with a feathered hood and cape, both infused with the lingering essence of Medivh’s soul. This 3-piece transmog pack also includes a new staff appearance that honors the past Guardians of Tirisfal.

Available in the Battle.net® Shop for a limited time*. Items from The Guardian Pack will arrive in a future rotation of the Trading Post, but no sooner than three months after the pack leaves the Shop.