While different bacterial species of the gut microbiota have been shown to improve the effectiveness of immune checkpoint inhibitors [81] a negative impact of H. pylori infection on the efficacy of cancer immunotherapies has been described in patients with non-small-cell lung cancer (NSCLC), where H. pylori seropositivity was associated with poor response to anti-PD-1 immunotherapy [71]. The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.