Even though the precise frequency of hyperprogression is yet to be established, this topic is far from anecdotal; it concerns 9% (n = 12/132) of the multi-tumoral cohort of the Gustave Roussy Institute and 29% (n = 10/34) of a multicentric French cohort of head and neck carcinomas under anti PD-L1 therapy (11). The gene discussed is CD274; the disease is head and neck carcinoma.