It's an MMO ARPG. It is a Diablo-esque thing, but in an MMO setting.

Lost Ark is a game that's already been released for 3 or so years, and was created by a company called Smilegate. Western players have been screaming for it, so Amazon bought licencing rights.

New World could have been a fantastic MMO, unfortunately Amazon had no idea what they were doing and had no interest in listening to their players. Lost Ark started out in Korea and people hated it, Smilegate listened, the game was fixed then people loved it, now Amazon is publishing it in the West to Smilegate's specifications.