Antibodies have emerged as important therapeutics for cancer treatment, with multiple clinically relevant mechanisms of action. They can manipulate tumour-related signalling, exhibit immunomodulatory properties, and promote anti-tumour immune responses. Recent advances in antibody engineering have led to the development of chimeric, humanized, and fully human monoclonal antibodies, which have improved clinical applicability. Over the past decade, antibodies have shown significant efficacy in treating various cancers, including those targeting tumour antigens, growth factor receptors, and the tumour microenvironment. Antibodies can be divided into five classes based on their heavy chain constant regions: IgM, IgD, IgG, IgE, and IgA. IgG is the most commonly used for cancer immunotherapy. Antibodies have two functional units: the fragment of antigen binding (Fab) and the constant fragment (Fc). The Fab contains the variable region, which binds to antigens, while the Fc fragment mediates immune effector functions, such as complement-dependent cytotoxicity (CDC), binding to Fc γ-receptors (Fc γR), and the neonatal Fc receptor (FcRn). IgG subclasses, particularly IgG1 and IgG3, are potent activators of the classical complement pathway. The binding of IgG to cell surfaces leads to C1q binding, activation of complement proteins, and subsequent tumour cell lysis. Fc γRs can transduce activating or inhibitory signals, with Fc γRIIIB (CD16B) being expressed on human neutrophils. Antibodies targeting tumour cells or the tumour microenvironment can inhibit growth factor receptors, induce apoptosis, and sensitize tumours to chemotherapy. Examples include cetuximab and trastuzumab, which target EGFR and HER2, respectively. These antibodies can also inhibit angiogenesis and promote immune responses. Antibodies can also target immune cells, such as CD40 and CTLA4, to enhance anti-tumour immune responses. Anti-CTLA4 antibodies like ipilimumab have shown promise in treating metastatic melanoma but can cause immune-related side effects. Fc domain modifications can enhance antibody efficacy by improving Fc γRIIIA binding and ADCC. Anti-CD25 antibodies can deplete regulatory T cells, enhancing anti-tumour immunity. Combination therapies with chemotherapy, radiation, and vaccines have shown improved outcomes in cancer treatment. For example, bevacizumab combined with chemotherapy has improved survival in colorectal cancer patients. Radiation therapy can enhance anti-tumour immunity through toll-like receptor activation. Future research aims to optimize antibody structures to enhance immune responses and develop new targets for cancer therapy. Advances in antibody engineering, such as bispecific antibodies and engineered protein scaffolds, offer promising approaches for improving cancer treatment. Overall, therapeutic antibodies continue to play a crucial role in cancer immunotherapy,Antibodies have emerged as important therapeutics for cancer treatment, with multiple clinically relevant mechanisms of action. They can manipulate tumour-related signalling, exhibit immunomodulatory properties, and promote anti-tumour immune responses. Recent advances in antibody engineering have led to the development of chimeric, humanized, and fully human monoclonal antibodies, which have improved clinical applicability. Over the past decade, antibodies have shown significant efficacy in treating various cancers, including those targeting tumour antigens, growth factor receptors, and the tumour microenvironment. Antibodies can be divided into five classes based on their heavy chain constant regions: IgM, IgD, IgG, IgE, and IgA. IgG is the most commonly used for cancer immunotherapy. Antibodies have two functional units: the fragment of antigen binding (Fab) and the constant fragment (Fc). The Fab contains the variable region, which binds to antigens, while the Fc fragment mediates immune effector functions, such as complement-dependent cytotoxicity (CDC), binding to Fc γ-receptors (Fc γR), and the neonatal Fc receptor (FcRn). IgG subclasses, particularly IgG1 and IgG3, are potent activators of the classical complement pathway. The binding of IgG to cell surfaces leads to C1q binding, activation of complement proteins, and subsequent tumour cell lysis. Fc γRs can transduce activating or inhibitory signals, with Fc γRIIIB (CD16B) being expressed on human neutrophils. Antibodies targeting tumour cells or the tumour microenvironment can inhibit growth factor receptors, induce apoptosis, and sensitize tumours to chemotherapy. Examples include cetuximab and trastuzumab, which target EGFR and HER2, respectively. These antibodies can also inhibit angiogenesis and promote immune responses. Antibodies can also target immune cells, such as CD40 and CTLA4, to enhance anti-tumour immune responses. Anti-CTLA4 antibodies like ipilimumab have shown promise in treating metastatic melanoma but can cause immune-related side effects. Fc domain modifications can enhance antibody efficacy by improving Fc γRIIIA binding and ADCC. Anti-CD25 antibodies can deplete regulatory T cells, enhancing anti-tumour immunity. Combination therapies with chemotherapy, radiation, and vaccines have shown improved outcomes in cancer treatment. For example, bevacizumab combined with chemotherapy has improved survival in colorectal cancer patients. Radiation therapy can enhance anti-tumour immunity through toll-like receptor activation. Future research aims to optimize antibody structures to enhance immune responses and develop new targets for cancer therapy. Advances in antibody engineering, such as bispecific antibodies and engineered protein scaffolds, offer promising approaches for improving cancer treatment. Overall, therapeutic antibodies continue to play a crucial role in cancer immunotherapy,