Immune microenvironment and strategy of immunotherapy in acral melanoma

Acral melanoma (AM) is a distinct subtype of melanoma that arises on sun protected skin of the palms, soles, and nail beds, and is the most common melanoma subtype in non-Caucasian populations. Despite recent advances in cancer immunotherapy, the efficacy of current immune checkpoint inhibitors in AM remains limited, necessitating tailored approaches for AM that are still undefined. Recent genomic and transcriptomic studies have revealed the unique genetic landscape of AM and its immunosuppressive tumor microenvironment. In this review, we discuss the characteristics of the AM immune microenvironment and highlight key differences compared with cutaneous melanoma. These insights may inform the development of more effective strategies to enhance antitumor immunity in AM.