CD274 and neoplasm: Blocking PD-L1 on DC or PD-1 on T cells can improve T cell priming and promote anti-tumor immunity.57 As priming of T cells with tumor-associated antigens could occur in BM,58 which is the site of B cell development,59 we surveyed its T and B cells to find similarities but also notable differences in young versus aged, (Figures 3A–C and S2A–H).