In fact, it has been seen that patients with low CXCR4 expression in cytotoxic T lymphocytes in peripheral blood have a better efficacy to anti-PD-1 ICIs in NSCLC because probably they are receiving trafficking orders from a higher expression of CXCL12 in tumor tissue [2,11]. The gene discussed is CXCR4; the disease is non-small cell lung carcinoma.