The ever-evolving list from Wizards of the Coast bans and restricts previously released cards, so that cards that end up becoming too powerful and give players an unfair advantage can't be used in tournaments
Starring as the main commander is the duo of Shiko and Narset, Unified, coming with the new Jeskai-specific ability flurry, letting you copy your second spell each turn so long as that spell targets a permanent or player
Picture this, you cascade on your opponents end step and cascade into a powerful spell
This requires Daxos, Blessed by the Sun or Pious Wayfarer to come down on turn three, but deploying this for two mana on turn four or turn five alongside another spell is pretty awesome
In a rule specific to drafting Double Masters, you also get to pick two cards whenever you open a pack, which means you can end up with a lot of powerful cards and a slightly stronger archetype as a result