The autopilot is an AI Assistance that uses the store's order history combined with the product(s) already present in the cart to make recommendations.
Using the store's order history, it attempts to recommend the product that is most purchased along with the contents of the shopping cart. The AI Auto-suggest helps you create automated offers for your customers. With the feature activated, In Cart Upsell, will go through the customer's cart, check the products they have in the cart, then pick;
1. Products commonly bought alongside what they have in the cart,
2. Products the customer is most likely to buy
This data is then used to create an offer of 1, 2, 3, or more products depending on the settings you made when setting up the AI Autosuggest functionality.
Please see the link to the article on how to setup the Autopilot