AbstractPurpose:. Malignant melanoma represents the most lethal skin cancer with germline predispositions thought to comprise 10% to 15% of all melanoma cases. No studies to date examine the immunologic features that may differentiate survival differences between germline pathogenic variant (gPV)–positive patients with melanoma from gPV-negative patients with melanoma.Experimental Design:. Adult patients with melanoma and clinical characteristics suggesting hereditary predisposition to cancer were prospectively recruited to undergo germline testing and flow cytometric analysis of peripheral immune suppressor cells.Results:. In this cohort, gPV-positive patients (n = 72) had a significantly improved melanoma-specific survival (MSS) compared with gPV-negative patients (n = 411; HRadj, 0.32; 95% CI, 0.13–0.82; P = 0.01). These survival improvements among gPV-positive patients were most apparent among cutaneous melanoma subtypes (HRadj, 0.12; 95% CI, 0.016–0.86; P = 0.03) and numerically i