Subjects must meet all of the following criteria in order to be eligible for this study: 1) Age ≥ 18 years old 2) ECOG performance status ≤ 2 3) Subjects with histologically or cytologically confirmed cancer diagnosis (invasive solid tumour or haematological malignancy) undergoing active systemic cancer treatment at the time of 1st dose of the anti-SARS-CoV-2 mRNA vaccine (such as chemotherapy, immunotherapy, targeted agents, endocrine therapy) in - non-metastatic setting or - metastatic setting (only 1st line therapy ) or undergoing follow-up after confirmed cancer complete remission without active cancer treatment for the last 12 months at the time of 1st dose of the anti-SARS-CoV-2 mRNA vaccine 4) Life expectancy > 6 months 5) Subjects who received the 2nd dose of mRNA platform vaccination against SARS-CoV-2 as per local guidelines within 6 months (maximum until 6 months and 3 weeks) prior to registration. 6) Urine pregnancy test negative for all female subjects of childbearing potential within 7 days prior to subject enrolment. 7) Signed Informed Consent form (ICF) obtained prior to any study related procedure. 8) Subject is willing and able to comply with the protocol for the duration of the study including treatment and scheduled visits and examinations.

Subjects must meet all of the following criteria in order to be eligible for this study: 1) Age ≥ 18 years old 2) ECOG performance status ≤ 2 3) Subjects with histologically or cytologically confirmed cancer diagnosis (invasive solid tumour or haematological malignancy) undergoing active systemic cancer treatment at the time of 1st dose of the anti-SARS-CoV-2 mRNA vaccine (such as chemotherapy, immunotherapy, targeted agents, endocrine therapy) in - non-metastatic setting or - metastatic setting (only 1st line therapy ) or undergoing follow-up after confirmed cancer complete remission without active cancer treatment for the last 12 months at the time of 1st dose of the anti-SARS-CoV-2 mRNA vaccine 4) Life expectancy > 6 months 5) Subjects who received the 2nd dose of mRNA platform vaccination against SARS-CoV-2 as per local guidelines within 6 months (maximum until 6 months and 3 weeks) prior to registration. 6) Urine pregnancy test negative for all female subjects of childbearing potential within 7 days prior to subject enrolment. 7) Signed Informed Consent form (ICF) obtained prior to any study related procedure. 8) Subject is willing and able to comply with the protocol for the duration of the study including treatment and scheduled visits and examinations.