PDCD1 and metastatic malignant neoplasm in the lymph nodes: In univariate analyses, progression-free survival was significantly associated with multiple factors including tumour stage (hazard ratio (HR), 4.85; 95% CI, 1.47-16; P= 0.01), tumour size (HR, 8.63; 95% CI,1.47-16; P= 0.039) HPV negativity (HR, 3.82; 95% CI, 1.23-11.92; P=0.021), lymph node metastasis (HR, 3.44; 95% CI, 1.05-11.7; P= 0.041), PD-1 expressing status (HR, 3.89; 95% CI, 1.29-11.71; P=0.016) and CD8+/CD4+ TIL ratio (HR, 7.1, 95% CI, 1.57-32.09; P=0.011).