Based on patients, who are treated in the University Cancer Center Hamburg (UCCH) and its contracted partner network, which comprises all cancer treating departments at the University Medical Center of Hamburg-Eppendorf (UKE), as well as 19 office-based oncologists and 20 surrounding hospitals, recruitment for the study will be done as follows:

(i) as a cancer patient during regular aftercare appointments who reports a current or past COVID-19 infection.

(ii) as an acute COVID-19 patient who reports a prevalent cancer diagnosis

Data will be collected as available from routine clinical care and includes demographic and biometric data, medical history, baseline data at inclusion as well as inpatient and intensive care unit admissions. Upon consent, patients will provide peripheral blood samples at time of inclusion and after 6 month. Recruitment is limited to a one-year period (April 2020 - April 2021).