CD274 and neoplasm: A poor OS was associated with non-operated patients [HR, 3.42 (1.15–10.16)] with low tumor MSLN expression [HR, 2.58 (1.09–6.10)], high levels of PD-L1, and low infiltration of T cells CD4+ in the TME [HR, 3.81 (1.58–9.18)].