Malignant pleural mesothelioma (MPM) is one of the most aggressive solid tumors, although multimodal therapies1, as well as immune checkpoint inhibitors targeting the programmed cell death protein-1 (PD1)/programmed cell death protein-1 ligand 1 (PD-L1) axis2,3 have improved the clinical outcome of patients with MPM. Here, PDCD1 is linked to malignant pleural mesothelioma.