CTLA4 and colorectal cancer: Durvalumab and tremelimumab can be combined with manageable adverse events.11 We hypothesized that a combined blockade of PD-L1 and CTLA-4 would provide greater anticancer activity and conducted a randomized phase 2 clinical trial to evaluate the efficacy of durvalumab and tremelimumab in patients with advanced refractory colorectal cancer.