Here, we report in detail on the [18F]FDG-PET scans acquired in the context of the IMCISION trial, wherein patients with locoregionally advanced HNSCC were treated with two cycles of nivolumab (anti-PD-1) monotherapy or nivolumab plus ipilimumab (anti-CTLA-4) before definitive surgery [7]. The gene discussed is CTLA4; the disease is head and neck squamous cell carcinoma.