CD274 and neoplasm: Currently, there are three FDA-approved predictive biomarkers of ICI response: PD-L1 expression by IHC, microsatellite instability/defective mismatch repair (MSI/dMMR) either by immunohistochemistry (IHC), polymerase chain reaction (PCR), or next-generation sequencing (NGS), and tumor mutational burden (TMB) by whole exome sequencing (WES) or NGS (6).