In the past decades, a major advancement has been the use of immune checkpoint inhibitors (ICIs) to block antibodies expressed on T lymphocytes, including cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) and programmed cell death protein-1 (PD-1) (Ansell et al., 2015; Wolchok et al., 2017), or their corresponding ligands expressed on tumor cells, such as programmed cell death 1 ligand-1 (PD-L1) (Herbst et al., 2016; Gulley et al., 2017; Choueiri et al., 2018). This evidence concerns the gene PDCD1 and neoplasm.