In this study, we assessed the expression of LAG-3 in the tumor microenvironment (TME) of melanoma metastases and evaluated the association between baseline immunohistochemical LAG-3 expression and clinical outcomes in patients with metastatic melanoma treated with either dual anti-LAG-3 + anti-PD-1 combination immunotherapy or triple anti-LAG-3 + anti-PD-1 + anti-CTLA-4 immunotherapy. The gene discussed is PDCD1; the disease is melanoma.