Nvidia CEO Jensen Huang resigned Thursday after his extramarital affair raised national security concerns, in a spectacular downfall for the longtime head of the chipmaker, a vital player in the artificial intelligence boom. The scandal has sent shares of the multi-trillion-dollar company plunging, and the exit of Huang, who has been a key promoter of the artificial intelligence boom, leaves Nvidia without its leather-jacket-clad leader at a crucial time for the sector.