In the present study, we examined the expression of CK17 in an expanded discovery cohort as well as an independent validation cohort of HNSCC patients treated with ICB to further investigate the clinical relevance of CK17 in ICB-treated HNSCC and provide a comprehensive analysis of the predictive value of CK17 and its association with PD-L1 and other clinicopathologic characteristics in accordance with the Reporting Recommendations for Tumor Marker Prognostic Studies (REMARK) guidelines [23]. Here, CD274 is linked to head and neck squamous cell carcinoma.