CTLA4 and metastatic melanoma: US melanoma patients with higher (≥–4.21) CTLA4 experienced a 35% lower risk of death (HR = 0.65 [95% CI: 0.34 - 1.26], p = 0.202) than those with lower (<–4.21) CTLA4. Likewise, in the US metastatic melanoma cohort, patients with higher (≥–4.73) CTLA4 experienced better prognosis and 24% lower risk of death (HR = 0.76 [95% CI: 0.43 - 1.35], p = 0.353) than those with lower (<–4.73) CTLA4. However, in the primary melanoma cohort, no assessment was made as broader CI did not support HR.