The focus now must be on understanding the genetic signatures most likely to be associated with a productive response to ICI therapy.46 Thus, our data suggested that non-invasive assessment of 18F-FDG-uptake potentially identifies the microenvironment of tumours with low CD8 + TILs and low expression of PD-L1 and that the evaluation of 18F-FDG-uptake has a potential to become a crucial biomarker for determining the cancer aggressiveness and adaptation of ICI treatment in patients with OSCC in the future. Here, CD8A is linked to cancer.