In the context of Industries CPQ (Configure, Price, Quote), the API method that needs to be called from the integration procedure to return pricing information from the out-of-the-box pricing plan ispriceCart. This method is responsible for calculating the prices of items in a cart based on the defined pricing rules and structures within the CPQ system. By invoking this method, the integration procedure can retrieve accurate and up-to-date pricing information for the items selected by the customer.