Human-in-the-loop: the details
It doesn’t mean reviewing everything. The usual approach is a threshold: what the system resolves with high confidence and low risk goes through on its own, and anything doubtful or expensive goes to a review queue. The checkpoint goes where a mistake costs: a payment, an email to a customer, a change to a case file, a decision that affects a person.
For it to work, reviewing has to be faster than doing the task by hand. That means showing the proposal next to the evidence—the original document, the doubtful field highlighted—and recording what was accepted and what was corrected. Those corrections are also the best material for improving the system. For automated decisions that affect people, the GDPR recognizes the right to obtain human intervention.