On ArcGIS Network Analyst's Privacy Page you can request and collect all the privacy and GDPR related information that ArcGIS Network Analyst is providing.
The privacy policy by is a legal document or statement that discloses how ArcGIS Network Analyst gathers, uses, discloses, and manges their customers' data.
The basis for Esri sharing, adding, uploading, hosting, accessing or sending personal data out of Europe. Vendors can also add a description of their own impact assessment for data transfers.