B2M and neoplasm: In the aspect of tumor cell intrinsic factors, the mechanism include absence of antigenic proteins (low mutational burden, lack of viral antigens, lack of cancer-testis antigens, overlapping surface proteins), absence of antigen presentation (deletion in TAP, deletion in B2M, silenced HLA), genetic T-cell exclusion (MAPK oncogenic signaling, stabilized β-catenin, mesenchymal transcriptome, oncogenic PD-L1 expression) and insensibility to T cells (mutations in interferon gamma, pathway signaling).