Department of Defense Principal Cyber Advisors Act of 2019 This bill requires each military department to designate a Principal Cyber Advisor, responsible for advising each department on cyber forces, cyber programs, and cybersecurity matters, including those relating to weapons systems, enabling infrastructure, the defense industrial base, and Department of Defense information services. The bill directs each department to review its current governance model for cybersecurity no later than January 1, 2021.