Notably, transcripts for PD-1 (Pdcd1) were observed only in T cell clusters (Fig. 4g and Extended Data Fig. 5b) whereas PD-L1 (Cd274) transcripts were more abundant in neutrophils, DCs and macrophages and PD-L2 (Pdcd1lg2) in DCs and not in EGFR+ cancer cells (Fig. 4f,g and Extended Data Fig. 5b). Here, PDCD1 is linked to cancer.