'Horizon Burning Shores' will take Aloy to a volcanic Los Angeles on April 19th

engadget.com:

Just like its predecessor, Horizon Forbidden West is getting an expansion. As revealed at The Game Awards, the Burning Shores DLC will arrive on April 19th. 

The DLC will pick up from where the sprawling story of Forbidden West left off. It will see Aloy travel to what was once Los Angeles, a region that's now home to a volcanic archipelago. She'll be able to explore the area by water or on the back of a Sunwing, a flying mount. Guerrilla Games says you can expect to encounter new characters and adventures. Ultimately, Aloy will have to battle an enormous machine and use all of her skills and abilities to take it down.

Unfortunately for fans who haven't been able to get their hands on a PS5, Burning Shores won't be coming to PS4. "To achieve this grand vision technically and creatively, we’ve made the difficult decision to focus all our efforts on making an incredible experience exclusively for the PlayStation 5 console," Guerrilla said. The studio plans to reveal more details about the DLC in the coming months.

Guerilla has at least one other Horizon project in the works. It will release Horizon Call of the Mountain as a PS VR2 launch title in February.