CD274 and hepatocellular carcinoma: Tan et al. (Tan et al., 2021) and Liu et al. (Liu et al., 2019a) found that HCC-derived exosomes encapsulated and transferred LOXL4 and miR-23a-3p into macrophages, thereby activated the expression of PD-L1 in TAMs to promote apoptosis or inhibit CD8+ T-cell function.