LAG3 and Cognitive impairment: The above detection of cognitive and microvascular injury indicators revealed no significant differences between the PBS‐Lag3‐WT and PBS‐Lag3‐ECs‐Cko groups, and PFFs still caused cognitive impairment and cerebral microvascular injury in Lag3‐ECs‐Cko mice, indicating that endothelial cell Lag3 is not the only factor controlling cognitive and cerebral microvascular function.