The independent effect of PD-1 expression status (PD-1high VS PD-1low) of CD8+ TILs on progression-free survival and overall survival was evaluated by Cox proportional hazards regression models adjusted for tumour stage, tumour size, lymph node metastasis, HPV infection status, tumour pathohistological classification, CD8+/CD4+ TIL ratio, PD-1 frequency on CD8+ TILs and Tim-3 frequency on CD8+ TILs (Supplementary Figure 2 and Tables 2, 3). Here, PDCD1 is linked to metastatic malignant neoplasm in the lymph nodes.