In addition, a basket Phase 1 study of patients with advanced solid tumours found that the combination of nintedanib and the PD-1 inhibitor pembrolizumab exerted a substantial antitumour effect, with a response rate of 25% (3 of 12 patients) (NCT02856425).35 In a cohort of patients with malignant pleural mesothelioma, 6 (21%) individuals achieved a partial response to this regimen.36 Our preclinical data show that the combination of PD-1 blockade and nintedanib as a CAF-targeted agent had an enhanced antitumour effect, supporting the rationale for these ongoing trials. Here, PDCD1 is linked to malignant pleural mesothelioma.