Fig. 1

Immunohistochemical staining of tongue and larynx squamous cell carcinoma FFPE tissue samples for PD-1, PD-L1, and CD45RO markers. A Shows different expression intensities of PD-L1 by tumor cells. B Represents examples of low and high expression of PD-1 and PD-L1 by immune cells, as well as low and high infiltration of CD45RO + immune cells. IC-PD-L1: PD-L1 expression by immune cells, TILs: tumor infiltrating lymphocytes