CD8A and head and neck squamous cell carcinoma: Analyses of 29 human papillomavirus (HPV)-negative HNSCC samples revealed four immunotypes based on CD8+ T cell density: fully infiltrated, stroma-restricted, immune-excluded, and immune-desert [7], all of which were independent of the tumor characteristics, T- and disease-stages, recurrence, and extra nodal extension (ENE) status.