PDCD1 and mesothelioma: In murine models of mesothelioma, it was demonstrated that mesothelioma tumor cells and CD8+ upregulated PD-L1 and PD-1, respectively, in response to anti-CSF-1R therapy alone, emphasizing the importance of incorporating anti-PD-1 therapy into anti-CSF-1R treatment regimens (Magkouta et al., 2021).