Metastatic melanoma patients received weight based pembrolizumab...There was significantly higher frequency of co-expression of CXCR6 and TIM3 on CD4+ T cells for PD (mean 21.5% CI 14.9% - 26.06%) compared to CR (mean 12.2% CI 9.40% - 14.99%) (p=0.003) and PR (mean 9.9% CI 7.76% - 12.05%) (p=0.0001). There was also significantly higher frequency of co-expression of CXCR6 and TIM3 on CD8+ T cells for PD (mean 32.59% CI 25.76% - 39.43%) compared to PR (mean 21.9% CI 18.22% - 25.56%) (p=0.032).