Paradoxically, in vitro analysis has demonstrated the promotion of a memory versus an effector signature in CD8 T cells exposed to CDK4/6i, which is independent of cell-cycle arrest, since it is not reproducible with other cell-cycle inhibitors, and these results were replicated in vivo in a small cohort of breast cancer patients and healthy donors [24,25] Thus, our unexpected results highlight the importance of more studies concerning T-cell response after vaccination. The gene discussed is CDK4; the disease is breast cancer.