Much attention has recently been focused on LAG-3, which may belong to the second wave of immune checkpoint targets along with the receptors of TIGIT and TIM-3, as it is expressed on tumor-infiltrating lymphocytes along with the immunoregulatory receptor PD-1 and is associated with T cell exhaustion (Le Mercier et al., 2015[29]). Here, PDCD1 is linked to neoplasm.