ENTPD1 and neoplasm: It was previously reported that CD39+ and PD-1+ TIL subsets can be enriched for tumor-specific T cells (Gros et al., 2014; Inozume et al., 2010; Balança et al., 2021; Li, 2020; Thommen et al., 2018; Simoni et al., 2018; Pauken et al., 2021; Zhu et al., 2021).