Window of Opportunity Study in Colorectal Cancer

Oral Capecitabine: 1000mg/m2 twice a day from Day 1 to 14 of a 3-week cycle, and IV Oxaliplatin: 130mg/m2 on Day 1

IV infusion of 200mg on Day 1 and Day 22

Capecitabine: Oral dose of 825mg/m2/day twice a day on radiation days with concurrent radiation median 50.4 Gy/ 28 fractions; or 5-FU: 225mg/m2/day concurrent with radiation

IV infusion of 200mg on Day 1 of each cycle

"* Oral Capecitabine: 1000mg/m2 twice a day from Day 1 to 14 of a 3-week cycle.~* IV Oxaliplatin: 130mg/m2 on Day 1 of a 3-week cycle.~* Pembrolizumab: IV infusion of 200mg on Day 1 of a 3-week cycle."

IV infusion of 200mg 21 days from the last CAPEOX/Pembrolizumab combination dose.

Performed after all medical intervention.