Kaplan–Meier analysis was used to evaluate OS and PD-1+CD8+ percentages; the data suggested that HPV− HNSCC with lower percentage of PD-1+CD8+ cells in IM_stroma had worse OS than that with higher percentage of PD-1+CD8+ cells in IM_stroma (Fig. 4h–j). Here, CD8A is linked to head and neck squamous cell carcinoma.