This guide goes over the details about Pokemon fusion in Pokemon GO, and how it applies to Necrozma and its Dusk Mane and Dawn Wings forms.
Pokemon GO Fest 2024: Dusk Mane and Dawn Wings Necrozma Pokemon Fusion Debut
Dusk Mane and Dawn Wings Necrozma, fusions between Necrozma and Solgaleo or Lunala, respectively, will make their Pokemon GO debut starting with the Pokemon GO Fest 2024 in-person locations (Sendai, Madrid, and New York City) followed by the global event.