When radiotherapy and chemotherapy were combined in patients with stage III–stage IV head and neck squamous cell carcinoma (HNSCC), there was a significant increase in polymorphonuclear MDSC population from PBMC at weeks 2 and 7 of treatment, with detectable STAT‐3 and PD‐L1 expression. The gene discussed is STAT3; the disease is head and neck squamous cell carcinoma.