CD274 and neoplasm: Current IO biomarkers fall into three main categories: surface markers like PD-L1, detected via immunohistochemistry, genetic biomarkers such as tumor mutation burden (TMB), mismatch repair-deficient (dMMR), high microsatellite instability (MSI), neoantigens, and antigen presentation mutations, requiring genomic analysis and circulating tumor DNA (ctDNA), analyzed from blood samples.