PD-L1 expression status in each tumor tissues of this study was unknown, because commercial monoclonal antibody (rabbit anti-human PD-L1 monoclonal antibody (EPR1161, Abcam, Tokyo, Japan)), which can cross react with canine PD-L1 in immunohistochemical staining experiments as shown in our previous study13, was no longer available, and no alternative product is currently available. The gene discussed is CD274; the disease is neoplasm.