This clinical trial compares minimal residual disease (MRD) testing with the Haystack blood test (assay) to the Signatera® assay for the early detection of the cancer returning (cancer recurrence) in patients with stage II-IV colorectal cancer (CRC) that can be removed by surgery (resectable). MRD testing looks for evidence of remaining tumor following treatment that is only apparent using highly sensitive techniques. There are few effective tools available outside of imaging to identify CRC patients with MRD who may be at the highest risk for cancer recurrence after surgery. Early detection of CRC recurrence after surgery is important, as it may increase the chance of curative (ability to cure) outcomes for patients with cancer recurrence. Currently, the Signatera assay is used to monitor whether CRC recurs after surgery, however it is not a very sensitive test. Early work with the Haystack assay suggests it may be more sensitive than the Signatera assay, which may be more effective for the early detection of cancer recurrence in patients with resectable stage II-IV CRC.