1. A method of potentiating chimeric antigen receptor-modified immune cells (CAR-MIC) cancer immunotherapy comprising administering at least one differentiating retinoic acid receptor (RAR) active agent, wherein the differentiating RAR active agent is a RAR? agonist, to a cancer patient who is receiving, has received, or is scheduled to receive, CAR-MIC, wherein the RAR? agonist is a CYP26 metabolism-resistant, RAR? selective agonist having a structure of general formula (I)
wherein R1 is H or C1-6 alky, R2 and R3 are independently H or F, and R4 is a halogen.