On the first of January 2020, Joe DeRisi was passing through the airport in Guangdong on his way to Cambodia. In addition to his lab at UCSF, he now ran a peculiar new institution called the Chan Zuckerberg Biohub. Created with a $600 million gift from the Facebook founder and his wife, the pediatrician Priscilla Chan, it had set itself a preposterous goal: to eliminate all disease on earth by the end of the twenty-first century.