CDK6 and neoplasm: As the CD4-Cre model deletes in all peripheral T cell subsets (45), the Cdk6fl/fl CD4-Cre mouse model does not dissect CD8+ T cell-intrinsic roles of CDK6 in vivo. Thus, we cannot exclude that the absence of any difference in anti-tumor responses in vivo is related to a complex interplay between phenotypes of different T cell subsets that compensate each other.