SPDL1 and neoplasm: Whereas the plasma concentrations of sPD-L1, sPD-1, and sCTLA-4 did not show a clear linear correlation with baseline tumor size among patients in cohort A overall (Supplemental Figure 14, A–C), a relation was observed between sPD-L1 and tumor burden for patients with hot tumors but not for those with cold tumors (Figure 5, H–J).