The UFC on ESPN era kicks off Saturday night in Brooklyn, New York, with a worthy champion-versus-champion superfight -- something that's all the rage these days. Having seen the buzz and excitement over superfights like Cormier-Miocic and Nunes-Cyborg in 2018, the trend now stretches into the lightest men's divisions as the reigning men's flyweight and bantamweight champs kick off 2019.