Follow the Trend and Go Retrograde

A pharmaceutical salesman started out as a public teacher within the system, took a leave of absence without pay, and joined the vigorous work wave. He joined the pharmaceutical industry and engaged in pharmaceutical sales. Starting from a grassroots front-line salesman, he witnessed the dynamic changes of the industry, experienced the ups and downs of the market, and experienced the hard work of a salesman. What kind of test and ending will be waiting for him?