Democrat socialists of America. They're a political party inside the Democrat party that's focused of progressive politics. They all refuse AIPAC donations, condemn Israel's genocide, want to tax the rich, and basically do everything government is supposed to.
Mamdani, Abdul El-Sayed, and the like are part of it I believe.
They want to form their own political party but understand in America people basically will not vote third party so they're trying to do a massive coup and push Democrat party hard left. They've been getting some massive wins recently too.