CD274 and mismatch repair cancer syndrome 1: Tumors with mismatch repair deficiency or PD-L1 amplification have been associated with remarkable responses to immune checkpoint inhibitors.40-42 On the other hand, we have previously reported that MDM2 amplification and EGFR alterations (both of which were discerned in the current patient example) were significantly associated with hyperprogression when anti–PD-1/PD-L1 agents were used.22 In this prior report, all four patients with hyperprogression and available data had negative PD-L1 expression; the one patient with available data had high TMB.