AUS patients with high (≥–5.91) CTLA4 levels experienced a 47% lower risk of death (HR = 0.53 [95% CI: 0.27 – 1.06], p = 0.074) than patients with lower (<–5.91) CTLA4. Specifically, in AUS metastatic melanoma cohort, patients with high (≥–5.93) CTLA4 experienced a better prognosis and a 55% lower risk of death (HR = 0.45 [95% CI: 0.2 – 1.02], p = 0.057) than those with lower (<–5.93) CTLA4. In contrast, in the primary melanoma cohort, no assessment was made as the hazard ratio (HR) was not supported by broader CI. This evidence concerns the gene CTLA4 and metastatic melanoma.