CXCR3-dependent T cell infiltration has been demonstrated in murine models of lymphoma, renal cell carcinoma, melanoma, and breast cancer [21–25], and is a prerequisite to the success of programmed cell death protein-1 (PD-1)/programmed cell death protein ligand 1 (PD-L1) blockade therapy [26]. The gene discussed is PDCD1; the disease is breast cancer.