Stimuli-Responsive Drug Delivery Systems for Enhanced Melanoma Immunotherapy

Melanoma results in the formation of malignant tumors and is the deadliest form of skin cancer with high mortality rate. Immunotherapy for melanoma has made great breakthroughs in recent decades. However, low patient response rates and side effects due to the immunosuppressive tumor microenvironment (iTME) and tumor heterogeneity limit the clinical application of melanoma immunotherapy. The tumor microenvironment (TME) exhibits characteristics such as weak acidity, hypoxia, and aberrantly expressed proteases. By exploiting these features, researchers have developed stimuli-responsive drug delivery systems (DDSs) to enhance antitumor immune responses in melanoma patients. This review aims to clarify how stimuli-responsive DDSs enhance melanoma immunotherapy and guide their use as therapeutic agents. We summarize the categorization and design of these DDSs, analyze their immune-enhancing pathways, and discuss current challenges and future prospects in the field.