Background:The incidence rate and mortality rate of melanoma have been increasing in recent decades. Increasing evidence has depicted the correlation between melanoma prognosis and immune signature. Therefore, the aim of this study is to develop a robust prognostic immune-related gene pairs (IRGPs) signature for estimating overall survival (OS) of melanoma.Methods:Gene expression profiling and clinical information of melanoma patients were derived from two public data sets, divided into training and validation cohorts. Immune genes significantly associated with prognosis were selected. Results:Among 1,646 immune genes, a 25 IRGPs signature was built which was significantly associated with OS in the training cohort (P=1.80×10−22; hazard ratio [HR] =9.50 [6.04, 14.93]). In the validation datasets, the IRGPs signature significantly divided patients into high- vs low- risk groups considering their prognosis (P=2.47×10−4; HR =2.99 [1.66, 5.38]) and was prognostic in multivariate analysis. Functional analysis showed that several biological processes, including keratinization and pigment phenotype-related pathways, enriched in the high-risk group. Macrophages M0, NK cells resting and T cells gamma delta were significantly higher in the high-risk group compared with the low-risk group. Conclusions:We successfully constructed a robust IRGPs signature with prognostic values for melanoma, providing new insights into post-operational treatment strategies.