To further investigate whether a small fraction of cancer cells that harbor sPD-L1 variants would protect the whole tumor from attack by cytotoxic lymphocytes, we tested the PD-L1 blockade antibody in mice subcutaneously injected with a mix of MC38/PD-L1v242 and MC38/PD-L1-WT in various ratios. Here, SPDL1 is linked to cancer.