A new study by Huang et al. in Cell identified the presence of tumor-specific memory CD8+ T cells in tumor-draining lymph nodes (TdLNs) and confirmed the critical role of this population in PD-1/PD-L1 immune checkpoint therapy for cancer.1 The work enriched our understanding of tumor-specific CD8+ T cell subsets and further refined the spatiotemporal mechanism of the antitumor effects of PD-1/PD-L1 immune checkpoint blockade (ICB). The gene discussed is CD8A; the disease is cancer.