CD274 and melanoma: Incidence of a type I (PD-L1+ and & TIL+) tumor microenvironment was found in 13.6% of ESCC specimens, which was lower than that found in advanced melanoma (38.0%) [15, 38], and this is the group believed to be representis largely responding to checkpoint blockade because of preexisting intratumoral T cells whose activity is attenuated by PD-L1 engagement.