In line with our findings, Coutzac et al. (2020) found that serum zonulin correlated with serum inflammatory proteins, such as tumor necrosis factor-α (TNFα) and monocyte chemoattractant protein 1 (MCP-1) in metastatic melanoma patients undergoing anti-CTLA-4 therapy [25]. Here, CTLA4 is linked to metastatic melanoma.