Immune checkpoint inhibitor (ICI) therapies have been evaluated for their effect on specific microbes in esophageal cancer, including cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed cell death 1 (PD-1)/PD-1 ligand (PD-L1) inhibitors (72). This evidence concerns the gene PDCD1 and esophageal cancer.