PDCD1 and neoplasm: Our findings from single-cell transcriptome analyses before and after treatment suggest that the tumor-suppressive mechanisms of PD-1 overlap with physiological PD-1 signaling, consistent with findings from the ITK-SYK mouse model, which showed that anti–PD-1 antibody treatment facilitated lymphoma progression by releasing the PI3K/AKT and PKCθ/NF-κB pathways and inhibiting the tumor-suppressive PTEN pathway in malignant T cells (19).