In August 2021, Dynamax was introduced into the game. Dynamax is a feature introduced in Pokémon Sword & Shield that allows for your Pokémon to grow in size and utilise Max Moves. Max Moves have special effecta and are far more powerful than the usual moves.
While in the main games, these last three turns, in Pokémon Masters EX, Dynamax lasts only one turn and acts akin to Sync Moves in that it is simply a powerful move. Each Max Move a Pokémon can have has different effects and some Sync Pairs have Passive Skills that react to the use of Max Moves either by the Sync pair, or against the Sync Pair.
You can only use Dynamax once per battle
List of Dynamax Capable Sync Pairs