The development of cancer metastases is particularly affected by the inhibition of immune activity associated with immune checkpoints (ICP), especially the PD1 (programmed death receptor 1) present, among others, on CD8+ T cells, natural killer cells and macrophages, and its ligand PD-L1 (programmed death receptor ligand 1) presented on cancer cells (31, 32). The gene discussed is CD8A; the disease is cancer.