CD274 and neoplasm: Unfortunately, MMs are poorly immunogenic, regardless of their intracellular mutational status, probably due to their lack of ability to induce a strong adaptive immune response in the tumor microenvironment; the reduced susceptibility to PD-1/PD-L1 and/or CTLA-4 blockade is highlighted by the extremely poor clinical outcomes of patients with advanced MM using immune checkpoint inhibitors [51].