PDCD1 and neoplasm: Spectra assigns this tumor reactivity marker27 a high weight in tumor reactivity but not exhaustion and strongly weights genes related to TCR signaling, T cell activation and cytotoxicity in the tumor reactivity factor, whereas the exhaustion factor mostly includes genes encoding exhaustion-inducing transcription factors (TOX21,22 and NR4A1 (ref. 28)) and PDCD1 (PD-1) (refs. 21,22).