Additionally, 28% of CUP tumors harbored one or more predictive biomarkers, such as microsatellite instability-high (MSI-H), Programmed death ligand-1 (PD-L1) positive and/or tumor mutation burden high (TMB-H), associating with the immune checkpoint blockade (Gatalica et al. 2018). This evidence concerns the gene CD274 and neoplasm.