Canine interleukin-24 (cIL-24) is a member of the IL-10 cytokine family—which includes IL-10, IL-19, IL-20, IL-22, and IL-26—and is homologous to human IL-24 (MDA-7), functioning in immune regulation, epithelial biology, inflammation control, and tumor suppression through IL-20 receptor–mediated JAK/STAT signaling pathways. Within animal health, cIL-24 is particularly relevant in veterinary oncology, where it is being explored for tumor-selective pro-apoptotic, anti-angiogenic, and immune-modulating effects in canine melanoma, lymphoma, mast cell tumors, and osteosarcoma—diseases that closely parallel human melanoma, non-Hodgkin lymphoma, breast cancer, colorectal cancer, lung cancer, pancreatic cancer, and osteosarcoma in their molecular drivers and tumor microenvironment. In coordination with other IL-10 family members such as IL-22 (epithelial barrier protection), IL-20 (skin and tissue inflammation), and IL-10 (anti-inflammatory regulation), cIL-24 may also contribute to immune balance in chronic inflammatory and immune-mediated disorders in dogs, including atopic dermatitis and inflammatory bowel disease, which resemble human psoriasis, Crohn’s disease, ulcerative colitis, rheumatoid arthritis, and atopic dermatitis. Because spontaneous cancers and inflammatory diseases in dogs arise naturally in immunocompetent animals, canine IL-24 and related IL-10 family cytokines support both improved veterinary therapeutic development and highly relevant translational animal models that advance comparative immunology and immuno-oncology research.