There are multiple assays with varying definitions of biomarker positivity, and in patients with the highest expression PD-L1 levels, a positive immunohistochemistry (IHC) test defined by ≥50% tumour PD-L1 expression, the response rate is only ~45%, while those with completely negative (<1%) tumour PD-L1 staining still have a response rate of ~10%.9–11. Here, CD274 is linked to neoplasm.