Inclusion Criteria:

          -  Age ≥18 years.

          -  Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1

          -  Have metastatic or locally advanced mismatch repair deficient/MSI-H disease.

          -  Patients must have received prior PD-1/PD-L1 inhibitor therapy

          -  Patients with the presence of at least one measurable lesion.

          -  Life expectancy of greater than 3 months.

          -  Patients must have adequate organ and marrow function defined by study - specified
             laboratory tests.

          -  Documented left ventricular ejection fraction (LVEF) ≥ 50% - 6 month prior to drug
             administration.

          -  Must use acceptable form of birth control while on study.

          -  Ability to understand and willingness to sign a written informed consent document.

        Exclusion Criteria:

          -  Known history or evidence of brain metastases.

          -  Require any antineoplastic therapy.

          -  History of prior treatment with anti-LAG3.

          -  Had chemotherapy, radiation, or steroids within 14 days prior to study treatment.

          -  Had any investigational cytotoxic drug within 4 weeks prior to study treatment.

          -  Have received any investigational drugs, a live vaccine, any allergen
             hyposensitization therapy, growth factors or major surgery within 28 days prior to
             study treatment.

          -  Hypersensitivity reaction to any monoclonal antibody.

          -  Has an active known or suspected autoimmune disease.

          -  Has a diagnosis of immunodeficiency.

          -  Prior tissue or organ allograft or allogeneic bone marrow transplantation.

          -  Requires daily supplemental oxygen

          -  History of interstitial lung disease.

          -  Significant heart disease

          -  History of encephalitis, meningitis, or uncontrolled seizures in the year prior to
             informed consent.

          -  Infection with HIV or hepatitis B or C at screening.

          -  Has an active infection.

          -  Unable to have blood drawn.

          -  Patient with uncontrolled intercurrent illness including, but not limited to,
             uncontrolled infection, symptomatic congestive heart failure, unstable angina
             pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would
             limit compliance with study requirements.

          -  Prior life-threatening toxicity to anti-PD-1, anti-PD-L1, anti-PD-L2,or anti-CTLA4

          -  Woman who are pregnant or breastfeeding.