This is a trial of prospective collection of serial blood samples after administration of COVID-19 vaccine in patients with cancer who are receiving active cancer treatment, planned to start therapy with 14 days of consent, or have had stem cell transplant. Cancer treatments and administration of vaccine are not controlled by the study.

Inclusion Criteria:

• Ability of participant OR Legally Authorized Representative (LAR) to understand this study, and participant or LAR willingness to sign a written informed consent
• Males and females age ≥ 18 years
• Patients with breast cancer, lung cancer, malignant melanoma or who have undergone stem cell transplant or chimeric antigen receptor (CAR) T cell therapy for a hematologic malignancy.

Other cancer types including hematologic malignancies may be allowed if they are receiving treatments outlined in section 4.1.4

• Solid Tumor patients and those with hematologic malignancies: Currently receiving active anti-cancer therapy, or planned to start within 14 days, with intravenous cytotoxic chemotherapy (oral or intravenous), intravenous chemoimmunotherapy combination, immunotherapy alone, an oral CDK 4/6 inhibitor. (This does not apply to recipients of stem cell transplant and CAR T therapy)
• Therapy may be neo/adjuvant or for metastatic disease
• Eastern Cooperation Oncology Group (ECOG) Performance status (PS) of 0-2

Exclusion Criteria:

* Life expectancy of < 12 months

Participants undergoing treatment for breast cancer, lung cancer and melanoma with chemotherapy, immunotherapy and/or oral anticancer agents, or have undergone stem cell transplantation