The official Japanese Pokémon Trading Card Game website announced the details for the
Zacian + Zamazenta Box (ザシアン+ザマゼンタBOX) which was released in Japan on December 27th, 2019. Exclusive Zacian and Zamazenta cards were included in this box set. It cost 1,500 yen plus tax.
Zacian + Zamazenta Box Details:
・ 27 cards
・ 6 Pokémon (4 types), 6 trainers (3 types), 15 basic energy cards
・ 3x Sword Booster Packs
・ 3x Shield Booster Packs
・ Tin Box
Source:
https://www.pokemon-card.com/info/2019/20191213_002222.html