From January 1st, 2022 until January 3rd, 2022 at 3:59pm PT, you can play as any Pokémon, regardless of if you own their UNITE license or not in Pokémon UNITE. Trial Licenses for all Pokémon will be available to use in Standard and Quick Battle Matches, including the new Tsareena and Dragonite Unite Licenses!


Source: https://twitter.com/PokemonUnite/status/1477069564139618305