profiled CD8+ T cells in human papillomavirus (HPV)‐positive head and neck cancer, and identified HPV‐specific TCF‐1+ PD‐1+ stem‐like TILs that proliferate and differentiate into effector‐like cells upon HPV peptide stimulation and PD‐1 blockade.[109] Similar results have been observed in chronic infection models. Here, PDCD1 is linked to head and neck cancer.