CTLA4 and neoplasm: To clarify the mechanism by which BMFs contributed to the compromise of anti-tumor immunity conferred by the aPD-L1 therapy, the expression of a series of immunomodulatory ligands (including CD70, CTLA-4, CD80, CD86, MHC-I, MHC-II, and PD-L1) on the surfaces of BMFs and tumor cells was analyzed by flow cytometry.