CD274 and cancer: Nevertheless, as PD-L1high ESCC was significantly associated with a concurrent CD3ihigh, CD8ihigh and PD1ihigh status in our cohort, one might hypothesize that high PD-L1 expression in ESCC might rather be interpreted as an adaptive mechanism of a given cancer in response to an immunoactive tumor-host relationship [41], that could therefore contribute to an improved disease course and speculatively, to a potential response towards immune checkpoint therapy [44].