Deregulated expression of immune checkpoint molecules, such as the immune checkpoint inhibitors (ICIs) PDCD1 (PD-1) and CD274 (PD-L1), in adjacent nontumor liver tissues from LM patients, including colorectal cancer, ovarian cancer, breast cancer, nasopharyngeal carcinoma, kidney cancer, and cervical cancer liver metastases, was validated by immunohistochemistry (IHC) staining. Here, PDCD1 is linked to colorectal cancer.