We analyzed single-cell sequencing data from various tumour tissues, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma (HCC and ICC), metastatic melanoma, head and neck squamous cell carcinoma (HNSCC), and colon cancer tissues, to identify novel markers associated with CD8+ T-cell dysfunction in the TME (Cillo et al, 2020; Ma et al, 2021; Tirosh et al, 2016; Zhang et al, 2020). This evidence concerns the gene CD8A and malignant colon neoplasm.