PDCD1 and neoplasm: Particularly treatments targeting the immune checkpoints programmed cell death 1 receptor (PD-1)/PD-1 ligand 1 (PD-L1) pathway and cytotoxic T-lymphocyte associated protein 4 (CTLA-4) have exhibited dramatic antitumor efficacy in various tumor entities (Chan et al., 2015, Brahmer et al., 2012, Brahmer et al., 2015, Topalian et al., 2012, Hamid et al., 2013, Wolchok et al., 2013, Larkin et al., 2015, Margolin et al., 2012, Berger et al., 2008, Ribas et al., 2016, Garon et al., 2015).