Tuna Mutis, MD, PhD, Amsterdam University Medical Center, Amsterdam, The Netherlands, describes mechanisms of resistance to chimeric antigen receptor (CAR) T-cell therapies in patients with multiple myeloma, including antigen escape and T-cell exhaustion. Certain targets such as B-cell maturation antigen (BCMA) may also not be highly expressed in the plasma cells of patients, reducing the efficacy of the treatment, and the quality of T-cells derived from patients may not be of standard. The tumor microenvironment additionally contributes to resistance to cell therapies, where their cytotoxicity may be reduced. This interview took place at the International Conference on Lymphocyte Engineering (ICLE) 2022.