Adding another layer of complexity, the MHC-II complex (encoded by HLA-DP, HLA-DM, HLA-DO, HLA-DQ, and HLA-DR) is canonically expressed by professional APCs to present antigens to CD4+ cells, but has also been found to be expressed by some tumor cells and to have an effect on ICB outcomes [80]. This evidence concerns the gene CD4 and neoplasm.