CD4+ T cells and CD8+ T cells in patients with CLL deviate from healthy individuals by the accumulation of memory T cells and loss of naïve T cells, increased expression of immune checkpoint receptors (i.e., PD1, TIGIT, CTLA-4), and increased activation [33,34,35,36,37,38]. The gene discussed is TIGIT; the disease is B-cell chronic lymphocytic leukemia.