IL2 and cancer: A particularly sensitive issue is the vaccination of cancer patients because the administration of a single dose of vaccine induces an immune response of specific T-cells IFN-γ and/or IL-2 SARS-CoV-2 in 48.2% of patients, and the second dose increases the response to 90.6% (significantly lower than that of the healthy population), because at three months post-vaccine the response decreases faster in patients with cancer.