Killer Mike, a Black man from Atlanta, Ga., and El-P, a white man from Brooklyn, N.Y., have transformed what should have been the twilight of their careers as rappers into their biggest spotlight yet. Known as the hip-hop duo Run The Jewels, they have headlined festivals worldwide, become action figures and Marvel comic book characters, spearheaded a worldwide countercultural movement, and played a significant role in the last two presidential elections.