On Touch Bar variants of the 2016 and 2017 MacBook Pros, Apple included a port on the logic board which taps into the soldered on storage.

To combat inaccessibility of user data in the case of board failure, Apple also produced a tool specifically for retrieving data via this port.

Apple themselves, or Authorized Service Providers are the most reliable way of getting data via this tool. They alone have access to its direct purchase.

Although exclusively available for Authorized use, these do crop up occasionally on eBay or other online marketplaces . You'll need to look for a 076-00236 Customer Data Migration Tool.

Be warned, they are often extremely expensive due to their rarity on the open market.