It is important to note that the effects of PD-1 signaling on monocytes appears to be disease-dependent as there is evidence that PD-1 blockade augments the influx of monocytes into the brain in Alzheimer’s disease (AD) models (Rosenzweig et al., 2019; Baruch et al., 2016; Ghareghani and Rivest, 2023). This evidence concerns the gene PDCD1 and Alzheimer disease.