The activation and balance of the body's immune system are crucial for defense against pathogens and for treating various diseases. The exploration of the use of nanomaterials for immune regulation has spanned several decades and has shown promising results because of their high biocompatibility and diverse functionalities. Since the discovery of carbon dots (CDs) in 2004, in-depth research on this novel nanomaterial has revealed that CDs are an ideal material for regulating the immune system. Researchers can synthesize various CDs based on different raw materials and reaction conditions. In this article, we have integrated the current CDs or CDs-based nanomaterials with immunomodulatory functions. Researchers have purposefully synthesized CDs by selecting different materials and methods, and these materials demonstrate the ability to regulate enzymatic reactions and energy conversion, which can directly modulate the body's immune activity. Post-synthesis modification provides more possibilities for developing novel immunomodulatory CDs nanomaterials. Through surface passivation, ligand conjugation, and the loading of drugs and antigens, the nanomaterials gain enhanced immunomodulatory capabilities, enabling more precise disease treatment. These strategies provide valuable insights into the development of immunomodulatory CDs nanomaterials, including nanozymes, adjuvants, vaccines, and drugs. By reviewing these achievements, we introduce valuable research experience and offer our own perspectives on the development of novel immunomodulatory CDs nanomaterials.