B2M and neoplasm: Recent research is concentrating on evaluating the effectiveness of new biomarkers, including DNA damage response (DDR) gene alterations, MHC genotypes, beta-2-microglobulin (B2M) deficiency, polymerase epsilon (POLE) mutations, Janus kinase 1/2 (JAK1/2) mutations, tumor-infiltrating T cells (TILs), peripheral T cells, and the gut microbiome [98].