Compassionate Access, Research Expansion, and Respect States Act of 2019 or the CARERS Act of 2019 This bill removes restrictions on, and creates new protections for, conduct and activities related to medical marijuana that are authorized by state law. Among other things, the bill does the following: eliminates regulatory controls and administrative, civil, and criminal penalties under the Controlled Substances Act for producing, possessing, distributing, dispensing, administering, testing, recommending, or delivering medical marijuana in compliance with state law; establishes a new, separate registration process to facilitate medical marijuana research; and authorizes health care providers employed by the Department of Veterans Affairs to make recommendations to veterans regarding participation in state marijuana programs.