Similarly, activating antibody targeting co-stimulatory molecules like OX40 (PF-04518600, NCT03971409) or 4-1BB (urelumab, PF-05082566, NCT03364348) are also in development in breast cancer, notably in the AVIATOR study with avelumab (NCT03414658) [117]. Here, TNFRSF9 is linked to breast carcinoma.