Interestingly, presentation of the antigen by cDC1s in draining lymph nodes (dLNs) of mice with locally implanted tumors derived from the same leukemia cells resulted in the robust activation of the identical CD8+ T cell population (Kline et al., 2018; Zhang et al., 2013), revealing that the environmental context in which a tumor antigen is encountered can confer drastically disparate CD8+ T cell functional states. The gene discussed is CD8A; the disease is leukemia.