PDCD1 and neoplasm: Bridged antigen pairings can be single targets like HER2/HER2 (biparatopic BsAb) or associations of two separate antigens like PD-1/CTLA4, PD-1/PD-L1, VEGF/Ang-2, IGF-1/IGF-2, etc. These BsAbs primarily target double signaling transductions to produce reinforced inhibited or activated impacts in lymphocytes or tumor cells.