Chamoto et al. [48] demonstrated that deleting of CD8+ T cells or ablating of TDLNs in PD-L1 mAb-treated mouse model of colon cancer resulted in impaired tumor growth inhibition by the PD-L1 mAb, suggesting TDLNs play a critical role in the initiation of CD8+ T cells and the generation of CTLs during PD-1 blockade therapy. This evidence concerns the gene PDCD1 and malignant colon neoplasm.