CD8A and cancer: As functional restoration of exhausted CD8+ T cells is important for effective antitumor immunity, advanced analytic tools (e.g., transposase-accessible chromatin using sequencing (ATAC-seq) and single-cell RNA sequencing (scRNA-seq)) have been applied to identify the epigenetic characteristics and transcriptomes of exhausted CD8+ T cells to improve our understanding of cancer immunotherapy (Thommen et al., 2018; Wang et al., 2019a; Khan et al., 2019; Kim et al., 2020).