Background: B7-H6 (NCR3LG1) can bind to NKp30 to trigger antitumor NK cell activation and cytokine secretion. Our previous studies have shown that in gastric cancer, B7-H6 high expression was associated with better prognosis and the low expression of B7-H6 group was correlated with better immune microenvironment. However, the effect of B7-H6 expression on immunotherapy is unknown. Herein, we used the data from a clinically annotated cohort of melanoma patients treated with ICI to analyze the influence of B7-H6 expression on immunotherapy. Methods: The gene expression profile, gene mutation information and clinical data were extracted from the supplementary data in melanoma cohort (PMID: 31792460). Maximally selected rank statistics was used to select the optimum threshold for B7-H6 expression, and the patients was divided into two groups according to the expression of B7-H6, high group and low group. Kaplan-Meier survival analysis was used to evaluate the influence of B7-H6 expression on OS prognosis. Associations between variables and OS survival were tested using univariate and multivariate Cox and displayed by forest (R package). Results: We selected 3.14 as the optimum threshold of B7-H6 expression, and the patients was divided into high group (B7-H6 expression＞3.14) and low group (B7-H6 expression≤3.14). The results showed that low group was significantly associated with longer overall survival (p value = 0.048) in cohort of melanoma patients treated with anti-PD1 ICI, which was consistent with our previous results that low expression of B7-H6 group was correlated with better immune microenvironment. We selected primary lesion type, TMB and the expression of B7-H6 factors for univariate and multivariate analysis. TMB-H (top 25%) (p value = 0.051) and B7-H6 (p value = 0.051) low expression were associated with a better OS. Then the patients were divided into four groups according to the TMB and B7-H6 expression and analyzed the difference in the four groups. The results showed that in patients with TMB-L, B7-H6 low group had significant better OS than the B7-H6 high group (p value = 0.032). Conclusions: The low B7-H6 expression was correlated with better efficacy immunotherapy. The effect of B7-H6 expression on immunotherapy needs to be further prospective trial validation.