The heist is called the Cayo Perico Heist and features a bunch of new design to the heist mechanics. For one, you can do the entire heist solo if you wish. Featuring an all-new island heist location, epic beach parties with high-profile musical guests and much more, Cayo Perico offers the score of a lifetime to those who can breach its defenses. You can learn more about this heist here.
Additionally, in case you missed it, the Music Locker, a new underground club, is also coming to GTA Online on December 15. You can find this music club beneath the Diamond Casino. New gameplay features will be introduced like dancing with a partner, in addition to new dance moves for all.