Inclusion Criteria:

          -  Recurrent and/or metastatic unresectable colorectal cancer with hepatic metastases

          -  Hepatic metastases present which are amenable to biopsy

          -  Prior treatment with, contra-indication to or refusal of a fluoropyrimidine,
             irinotecan, oxaliplatin and an anti-EGFR targeted therapy (if RAS wild-type [wt]) as
             well as a PD-1 or PD-L1 targeted drug if MSI-H/dMMR

          -  No chemotherapy, radiotherapy, major surgery, or biologic therapy within 3 weeks of
             protocol treatment

          -  An Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2

          -  Have measurable disease per RECIST 1.1 criteria present

          -  Ability to swallow and retain oral medication

          -  Participants of child-bearing potential must agree to use adequate contraceptive
             methods (e.g., hormonal or barrier method of birth control; abstinence) prior to study
             entry; should a woman become pregnant or suspect she is pregnant while she or her
             partner is participating in this study, she should inform her treating physician
             immediately

          -  Platelet >= 75,000/uL

          -  Hemoglobin >= 9 g/dL

          -  Hematocrit >= 27%

          -  Absolute neutrophil count (ANC) >= 1500/uL

          -  Creatinine < = institutional upper limit of normal (ULN) OR

          -  Creatinine clearance >= 50 mL/min for patients with creatinine levels greater than ULN

          -  Total bilirubin =< 1.5 X institutional ULN or for patients with known Gilbert's
             Syndrome total bilirubin <= 3 x ULN

          -  Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase [SGOT]) and
             alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT]) =< 2.5 X
             institutional ULN

          -  Plasma amylase =< 1.5 X institutional ULN

          -  Lipase =< 1.5 X institutional ULN

          -  Participant or legal representative must understand the investigational nature of this
             study and sign an Independent Ethics Committee/Institutional Review Board approved
             written informed consent form prior to receiving any study related procedure

        Exclusion Criteria:

          -  Patients currently treated with systemic immunosuppressive agents, including steroids,
             are ineligible until 3 weeks after removal from immunosuppressive treatment

          -  Patients with active autoimmune disease, requiring ongoing immunosuppressive therapy
             or history of transplantation

          -  Patients who are pregnant or nursing; women of childbearing potential (WOCBP) will
             have to undergo a urine pregnancy test as part of screening

          -  Untreated central nervous system (CNS) metastases

          -  Cardiac risk factors including:

               -  Patients experiencing cardiac event(s) (acute coronary syndrome, myocardial
                  infarction, or ischemia) within 3 months of signing consent

               -  Patients with a New York Heart Association classification of III or IV

          -  History of upper gastrointestinal ulceration, upper gastrointestinal bleeding, or
             upper gastrointestinal perforation within the past 3 years; patients with ulceration,
             bleeding or perforation in the lower bowel are not excluded

          -  Prior allergic reaction or hypersensitivity to celecoxib, or non-steroidal
             antiinflammatory drugs (NSAIDs) or any study agents which would prevent completion of
             protocol therapy

          -  Patients are ineligible if they plan on regular use of NSAIDs at any dose more than 2
             times per week (on average) or aspirin at more than 325 mg at least three times per
             week, on average; low-dose aspirin not exceeding 100 mg/day is permitted; patients who
             agree to stop regular NSAIDs or higher dose aspirin are eligible and no wash out
             period is required

          -  Received an investigational agent within 30 days prior to enrollment

          -  Unwilling or unable to follow protocol requirements

          -  Patients with known serious mood disorders

          -  Any additional condition which in the investigator?s opinion deems the participant an
             unsuitable candidate to receive the study drugs