Accumulating evidence points to a beneficial effect ofvagus nerve activity in tumor development. The vagus nerve is proposed to slow tumorigenesis because of its anti-inflammatory properties mediated through ACh and the α7nAChR. Since α7nAChRs are widely expressed by many types of immune cells we hypothesized that the vagus nerve affects the tumor microenvironment and anticancer immunity. We found direct evidence in studies using animal cancer models that vagus nerve stimulation alters immunological responses relevant to the tumor microenvironment. Also studies in pathologies other than cancer suggest a role for the vagus nerve in altering immunological responses relevant to anticancer immunity. These results provide a rationale to expect that vagus nerve stimulation, in combination with conventional cancer treatments, may improve the prognosis of cancer patients by promoting anticancer immunity.