Subsequently, they engaged MSR1-deficient mice to assess the impact of the PD-1 inhibitor in AD, revealing that these mice lacked the capacity to react to PD-L1 blocking antibody and demonstrated no improvement in cognitive function, suggesting an indispensable role of MSR1-expressing macrophages in the reparative process [21,22,29,30]. This evidence concerns the gene MSR1 and Alzheimer disease.