After working in the United States for more than a decade, Zheng Yefeng felt he had hit a glass ceiling. He also saw that the gap in artificial intelligence between China and the US was narrowing.

Last year Zheng, who worked as a researcher at Siemens Healthcare in New Jersey, made a decision that addressed both problems. He accepted an offer to head up the medical research and development team at Tencent's YouTu artificial intelligence lab in Shenzhen, known as China's Silicon Valley.