It is noteworthy to report that sPD-L1 FC vs. baseline, already measured after the first cycle of therapy, were found to be significantly associated to a longer OS of mesothelioma patients, providing fundamental support to the role of changes in circulating sPD-L1 as a non-invasive biomarker for an early prediction of response to immunotherapy. The gene discussed is SPDL1; the disease is mesothelioma.