CD274 and breast neoplasm: We hypothesize that, although TN breast tumors may effectively attract T lymphocytes at some point in their progression, these lymphocytes probably have their effector activity suppressed by the co-recruitment of immunosuppressive cells (M2 macrophages and regulatory lymphocytes) and the acquisition of an exhausted phenotype due to the PD-L1 expression, nevertheless this needs to be further validated.