Next, to determine the effect of platelet PD-L1 on immune cell infiltration within tumors, we performed immunohistochemistry on excised MC38 PD-L1 KO tumors and observed a decreased number of tumor-infiltrating CD8+ cells in tumors from mice transfused with PD-L1+/+ mouse platelets (Fig. 1f,g). The gene discussed is CD8A; the disease is neoplasm.