The role of other potential biomarkers for prognosis such as Programmed Death-Ligand 1 (PD-L1), circulating DNA (ctDNA) and Tumor Microenvironment Burden (TMB), and promoter hypermethylation of MLH1 gene as a prognostic biomarker for GC with MSI-H [44,45] are further under investigation. The gene discussed is CD274; the disease is gastric cancer.