Inclusion Criteria:

1. Patient is at least 18 years of age or older.
2. Eastern Cooperative Oncology Group performance status ≤ 2.
3. Patients who are able to consent to and provide residual tumor tissue for research. Bone marrow specimens are excluded as acceptable tumor tissue.
4. Patients with a new diagnosis of Stage I to IV aggressive non-Hodgkin lymphoma (NHL) including all aggressive large B-cell lymphoma (DLBCL, HGBCL, PMBCL), T-cell lymphoma (PTCL, ALCL), follicular lymphoma (FL) grade 3B, or transformed FL.
5. Patients who are planning to receive six cycles of first-line therapy with an anthracycline-based chemotherapy regimen as per the standard of care.
6. Radiographically measurable disease with at least one hypermetabolic lesion by Lugano classification on baseline FDG PET/CT or FDG PET (radiographically measurable disease by CT with intravenous contrast is allowed if FDG-PET/CT is not available).
7. Able to tolerate blood draws according to Natera standard process.

Exclusion Criteria:

1. Diagnosis of an indolent lymphoma that does not require immediate intervention, Hodgkin lymphoma, small lymphocytic lymphoma (SLL), or chronic lymphocytic leukemia (CLL). Other NHL diagnoses beyond DLBCL, aggressive TCLs, and grade 3B or transformed FL.
2. Diagnosis of aggressive NHL that has a circulating, leukemic component, bone marrow or blood involvement.
3. History of an allogeneic stem cell transplant or other organ transplant.
4. Prior history and treatment for any cancer within the past year or another active cancer, with the exception of participants who have undergone surgical removal of skin squamous cell or basal cell cancers.
5. Clinical ctDNA-MRD testing by any platform.
6. Concurrent treatment that includes an investigational agent.