A retrospective, multicenter study using TriNetX identified adult melanoma patients receiving anti-PD-1 monotherapy (pembrolizumab or nivolumab) (Cohort 1: n = 10,586) and patients receiving anti-PD-1/CTLA-4 combination therapy (nivolumab + ipilimumab) (Cohort 2: n = 5,705). Here, CTLA4 is linked to melanoma.