Role of CXCR3 signaling in response to anti-PD-1 therapy.

•The first infusion of anti-PD-1 antibody rapidly increases CXCR3+ T cells in blood in melanoma and head and neck cancer patients.•Retention of CXCR3+ T cells in blood is associated with the resistance to anti-PD-1 therapy.•CXCR3-dependent T cell tumor accumulation is required for effective anti-PD-1 immunotherapy.•Intratumoural injection with recombinant CXCL9/10 improved the anti-PD-1 antibody treatment