On the other hand, patient data implicates breast cancer TAMs as the immune population with the highest expression of checkpoint ligand Programmed Death-Ligand 1 (PD-L1) (30), being responsible for direct suppression of immune effectors (23) and for the recruitment of peripheral immunosuppressive myeloid cells and T regulatory cells (TRegs) (22, 31–33). The gene discussed is CD274; the disease is breast cancer.