Spatial distribution imaging analysis (multiplex immunofluorescence) suggested that a small fraction of CD8+PD-1+ T cells are also GITR+ (FoxP3–) within inflamed and excluded compartments of HNSCC, including the tumor, stroma and tumor-proximal lymph node aggregates (Fig. 2e and Extended Data Fig. 2c). This evidence concerns the gene PDCD1 and head and neck squamous cell carcinoma.