CD274 and melanoma: In melanoma, PD-L1 and TIL status were proposed to classify the TME into four different types, including Type I (TIL+, PD-L1+), Type II (TIL-, PD-L1-), Type III (TIL-, PD-L1+), Type IV (TIL+, PD-L1-).[16, 17] However, details about which cell type to be included in TIL and the threshold criterion are not defined yet.