CD8A and colorectal carcinoma: Even though immunotherapy has proven successful in treating a subset of patients with CRC with MSI-H/dMMR, liver metastases diminish immunotherapy efficacy systemically in patients and preclinical models, as liver metastases result in an “immune desert” microenvironment either through macrophage-mediated T cell elimination (45) or through the “siphoning” of tumor antigen–specific CD8+ T cells into the liver (46).