CXCL9 and head and neck squamous cell carcinoma: Similarly, in head and neck squamous cell carcinoma, the knockout of K17 in immunocompetent mouse model also resulted in tumor regression due to alterations in IFN ‐γ and CXCL9, and PD-L1 expression and increased CD8+ T-cell infiltration, thereby sensitizing tumors to immune-checkpoint blockade [59].