CDK4 and neoplasm: Either CDK4/6 or mTOR inhibitors increase PD-L1 protein levels by disruption of CDK4/6/cullin3SPOP or mTORC1/p70S6K/β-TrCP pathway-mediated PD-L1 ubiquitination and degradation11,12, while the combination of CDK4/6 inhibitors with PD-L1/PD-1 blockade effectively enhances tumor immunotherapy11.