CD8A and neoplasm: circRNAs from tumor-derived exosomes establish immune suppression and escape, and dysregulation of exosomal circRNAs in the tumor microenvironment (TME) can induce the exhaustion and dysfunction of immune cells, such as CD8+ T cells, natural killer (NK) cells, and dendritic cells, and elicit upregulation of immune checkpoints, such as programmed death 1 (PD1) in T cells [10].