CD28-B7 is an important pair of immune co-stimulatory molecules, including CD28 and its ligands from the B7 family (B7-1/CD80 and B7-2/CD86). CD28 is a receptor on the surface of T cells, while B7 molecules are mainly expressed on antigen-presenting cells such as dendritic cells. The interaction between CD28 and B7 plays a crucial role in T cell activation and proliferation, promoting cytokine production by activating signaling pathways such as PI3K/Akt and MAPK. Specific gene expression and mutations may affect immune regulation and be associated with the occurrence and development of various immune-related diseases.