CD274 and cancer: Notably, PD-L1 is also regulated on the post-transcriptional and post-translational levels, as exemplified by miRNAs regulating PD-L1 mRNA stability; chemokine-like-factor (CKLF)-like MARVEL transmembrane domain-containing proteins 4 and 6 (CMTM4 and CMTM6), regulating PD-L1 protein translocation at the cancer cell membrane; and various modifications regulating PD-L1 localization and stability [65,66,67,68].