PDCD1 and neoplasm: Patients with PD-L1 expressing tumor could be potentially under-represented in the durvalumab arm; tremelimumab is an IgG2 monoclonal antibody anti-CTLA-4 and, as such, unable to induce the antibody-dependent cell cytotoxicity; moreover, we could not exclude a different activity of PD-1 and PD-L1 agents.