Inclusion Criteria:  Patients with solid malignancies treated with either IO or non-IO treatment. All categories of IO treatment allowed (immune-checkpoint inhibitors, bi-specific T cell engagers, cytokine agonists and others), as well as all categories of non-IO treatment (such as chemotherapy and targeted therapies). These can be given as part of standard of care or within participation in a clinical trial. Patients are allowed to have any of the approved vaccines in Canada, such as Pfizer, Moderna, AstraZeneca or their approved combinations. Patients must receive all appropriate doses of SARS-CoV-2 vaccination, as dictated by the respective vaccine schedules.  Exclusion Criteria:  None