HMGB1 and neoplasm: demonstrated that HCC cells secreted high mobility group box 1‐enriched exosomes to activate TIM‐1+ regulatory B cells expansion, which exhausted CD8+ T cells and induced an immunosuppressive microenvironment for HCC progression.[43] However, under the existing conditions, we cannot explore whether immune factors are involved in BM‐EV‐absorbed tumor microenvironment.