CMTM6 and cancer: Recently, two research groups independently identified the previously obscured chemokine-like factor-like MARVEL transmembrane domain containing 6 (CMTM6) as a crucial regulator of PD-L1 in a wide range of cancer cells, and discovered through a genome-wide screen method that CMTM6 binds PD-L1 and contributes to cell surface localization by preventing PD-L1 from being targeted for lysosomal degradation in various cancer cell types [28,29].