Age is a major risk factor for solid cancers, hitherto conventionally viewed in the context of the cell biology of carcinogenesis. However, if cancers are immunogenic, the immune system could protect against tumorigenesis ("immunosurveillance"), and vaccination or other immunomodulatory treatments should be therapeutically beneficial, as has been recently dramatically documented in a fraction of patients with certain tumors responding to immune checkpoint blockade. This begs the question that if immunity decreases with age ("immunosenescence"), this may contribute to increased cancer disease in the elderly and a lower likelihood of clinical benefit from immunotherapy. This brief review weighs up the evidence for and against a negative impact of immunosenescence on cancer control.