PDCD1 and head and neck cancer: PD-1+CD8+T cells predict significantly worse OS in pancreatic cancer (HR=3.304, 95%CI 1.167-9.357, p=0.024), and significant worsening of DFS in gastric cancer and head and neck cancer (HR = 2.228, 95% CI 1.748-2.839 p<0.0001; HR = 2.972, 95% CI 1.194-7.395, p=0.019, respectively), but was associated with improved OS and DFS in triple negative breast cancer (OS: HR = 0.544, 95% CI 0.302-0.982, p= 0.043; DFS: HR =0.46, 95% CI 0.303-0.699, p<0.0001).