Advancements in sequencing and screening technology have made monoclonal antibodies more accessible, cost-effective, and precise. These drugs effectively target pathogens and cancer cells and even regulate metabolic pathways by focusing on specific intermediates. Monoclonal antibodies play a key role in mitigating a rise in occupation-related cancers, neurodegenerative disorders, and multidrug-resistant organisms. Here, we review the origins, mechanisms, and applications of this important drug class and explore future avenues for research.