Recombinant Anti-CD89 x Anti-EGFR Bispecific Antibody (Diabody-CH3) is a fusion protein of two diabodies connected together by a CH3 region. In a diabody, the two scFvs with short linkers are from anti-CD89 and anti-EGFR antibodies. The VH and VL domains form an inter-chain pairing. The diabody with different specificities is fused to each of the CH3 chains, which results in 2+2 antigen-binding valency and extends the half-life of this BsAb. This BsAb can retarget macrophages to tumor cells. It is designed for the research of Head and neck cancer; Colorectal cancer (CRC); Glioblastoma multiforme (GBM); Squamous cancer; Non-small cell lung cancer (NSCLC); Solid tumors therapy.