1. Arm 1 only: Patients with MSI positive colorectal cancer 2. Arm 2 only: Patients with MSI negative colorectal cancer 3. Arm 3 only: Patients with MSI positive non-colorectal cancer 4. Arm 4 only: patients with hypermutated MSI negative cancer 4. Have measurable disease 5. ECOG Performance Status of 0 to 1 6. Adequate organ function as defined by study-specified laboratory tests 7. Must use acceptable form of birth control through the study and for 28 days after final dose of study drug 8. Signed informed consent form 9. Willing and able to comply with study procedures 10. Agree to have a biopsy of their cancer 11. Patients with colon cancer must have received at least two prior cancer therapy regimens.