PDCD1 and neoplasm: In one study, a combination of scRNA-seq and intravital live cell imaging showed that IL-12 was secreted by cDC1-like cells in response to interferon-γ (IFN-γ) produced by CD8+ T cells bound to an anti- programmed cell death protein-1 (PD-1) antibody; this crosstalk was necessary for re-activation of exhausted T cells and subsequent anti-tumour responses31.