SPDL1 and cancer: In patients with mesothelioma treated with the anti-PD-L1 durvalumab combined with the anti-cytotoxic T-lymphocyte antigen (CTLA)-4 tremelimumab, circulating sPD-L1 levels increased during therapy, supporting its role as a predictive biomarker of response to anti-PD-L1 therapy in cancer and the specific involvement of PD-L1 targeting in the release of its soluble form [36].