For example, lung cancer cells secreted exosomal miR-21 and miR-29a, which could bind to TLR8 and stimulate the activation of NF-κB, leading to product the pro-inflammatory cytokines and promote tumor proliferation and metastasis.128 Exosomes containing hY4 derived from chronic lymphocytic leukemia (CLL) could be transferred to monocytes leading to key CLL-related phenotypes, including the release of the cytokines IL-6, CCL2, CCL4, and the promotion of PD-L1 expression. Here, CCL2 is linked to B-cell chronic lymphocytic leukemia.