Cheng Wei and Jean Liu

Didi Chuxing made headlines last year for buying Uber's China operations, besting its American rival in the battle for the biggest taxi market on the planet. Since then, the country's homegrown ride-hailing giant and its leaders -- Wei, CEO, and Liu, president -- have been on a tear: a $5.5 billion funding round valuing the company at more than $50 billion; investments extending its reach into Europe, the Middle East, and Africa; and a new A.I. lab in Mountain View, its self-driving competitors' backyard. Strap in: Didi's ride to dominance is just getting started.