CD274 and colorectal carcinoma: Nevertheless, in the KEYNOTE-016 and KEYNOTE-028 trial, the efficacy of PD-1/PD-L1 inhibitors for CRC with microsatellite-stable (MSS)/proficiency mismatch repair (pMMR), which accounts for 80-90% of patients with CRC, was dismal, with an ORR of 0% (11, 15, 16).