Fig. 1

Immunohistochemical features of PD-L1, CD8⁺, FOXP3⁺, and PD-1⁺. (A-C) PD-L1 is expressed in three major patterns: a “Focal” PD-L1 expression in tumor cells and immune cells (red arrows). b “Diffuse (positive ≥10% of tumor cells)” PD-L1 expression in tumor cells and no staining in immune cells. c PD-L1 expression in immune cells only. (D-F) Note the high population in each line of tumor-infiltrating lymphocytes (TILs); d CD8^+/high TILs, e FOXP3^+/high TILs, and f PD-1^+/high TILs