Blood-based soluble immune checkpoint-related proteins, like soluble PD-L1 (sPD-L1), are linked to the prognosis of advanced lung cancer and might serve as potential indicators for predicting the effectiveness of ICIs (120).The potential of sPD-L1 as an alternative marker for PD-L1 TPS is still being studied. The gene discussed is SPDL1; the disease is lung cancer.