However, since some PD-L1 negative patients benefit from targeting the PD-1/PD-L1 axis [17,18,19,20], it has been postulated that the spatial heterogeneity of PD-L1 expression in tumour tissue, which has been conclusively reported in previous studies [21,22,23], makes PD-L1 scoring in single tumour biopsies not representative for the entire tumour PD-L1 status. The gene discussed is PDCD1; the disease is neoplasm.