CTLA4 and colorectal carcinoma: In a first-in-human signal-seeking study, 34 patients with proficient-mismatch-repair/microsatellite-stable pMMR/MSS CRC received the oncolytic vaccinia virus pexastimogene devacirepvec (Pexa-Vec) in tandem with the PD-L1 blocker durvalumab, with or without the CTLA-4 antagonist tremelimumab (158).