You must have an ECOG performance status of 0 or 1.

You must have histologically/pathologically confirmed colon adenocarcinoma (T1-3, N1/N1c) with R0 resection accordingly to AJCC 8th edition criteria. NOTE: Patients with pathologic stages II or IIIC colon adenocarcinoma with R0 resection who have a commercially obtained Signatera™ ctDNA+ve assay result post-operatively meeting all timelines and eligibility requirements otherwise, are eligible for enrollment and inclusion in Cohort B.

You must have no radiographic evidence of overt metastatic disease within 28 days prior to study entry (CT with IV contrast or MRI imaging is acceptable and must include chest, abdomen, and pelvis).

The distal extent of the tumor must be greater than or equal to 12 cm from the anal verge on colonoscopy or above the peritoneal reflection as documented during surgery or on pathology specimen (i.e., excluding rectal adenocarcinomas warranting treatment with chemoradiation).

You must have had an en bloc complete gross resection of tumor (curative resection). Patients who have had a two-stage surgical procedure, to first provide a decompressive colostomy and then in a later procedure to have the definitive surgical resection, are eligible.

Colon cancer histology other than adenocarcinoma (i.e., neuroendocrine carcinoma, sarcoma, lymphoma, squamous cell carcinoma, etc.).

Pathologic, clinical, or radiologic overt evidence of metastatic disease. This includes isolated, distant, or non-contiguous intra-abdominal metastases, even if resected.

Tumor-related bowel perforation.

History of prior invasive colon malignancy, regardless of disease-free interval.

History of bone marrow or solid organ transplantation (regardless of current immunosuppressive therapy needs). Bone grafts, skin grafts, corneal transplants and organ/tissue donation are not exclusionary.

Any prior systemic chemotherapy, targeted therapy, or immunotherapy; or radiation therapy administered as treatment for colorectal cancer (e.g., primary colon adenocarcinomas for which treatment with neoadjuvant chemotherapy and/or radiation is warranted are not permitted).

Other invasive malignancy within 5 years before study entry. Exceptions are colonic polyps, non-melanoma skin cancer or any carcinoma-in-situ.

Synchronous primary rectal and/ or colon cancers.