LILRB4 and plasma cell myeloma: Leukocyte immunoglobulin‐like receptor B4 (LILRB4), a member of the LILR family located on 19q13.4, facilitates immune evasion in various cancers, including multiple myeloma, lung cancer and gastric cancer, by interacting with immune cells within the tumour microenvironment [19, 20, 21, 22].