Starbucks COO Roz Brewer is leaving the coffee giant. AP Photo/Ted S. Warren Starbucks chief operating officer Roz Brewer is leaving the company. Brewer will become the CEO of Walgreens, the Wall Street Journal reports. The new job will make Brewer the only Black female CEO of a Fortune 500 company. Visit Business Insider's homepage for more stories. Starbucks chief operating officer Roz Brewer is stepping down from the role, the coffee giant announced on Tuesday.