CD274 and neoplasm: In the KEYNOTE-028 basket trial, a multicenter phase Ib study with 20 cohorts of patients with PD-L1-positive advanced solid tumors, the efficacy of pembrolizumab, another anti-PD-1 monoclonal antibody, was evaluated in 24 patients with advanced ASCC who had a PD-L1-positive tumor and had failed one prior standard therapy.