CDKN1B and neoplasm: Increasing evidence indicates that dysregulation of Jab1/COPS5 contributes to tumorigenesis by functionally interacting with several tumour‐related proteins, such as the cyclin‐dependent kinase inhibitor 1B (p27) and 1C (p57), p53, SMAD4/7 and programmed death‐ligand 1 (PD‐L1).4, 5, 6, 7, 8, 9, 10