"Walmart Stores Chief Operating Officer Judith McKenna was named president and CEO of the company's international unit effective February 1, 2018. The role is seen as a stepping stone to the top job at the world's largest retailer with current CEO Doug McMillon and his predecessor Mike Duke having run the international unit previously. If international is such an important part of the company, what can Walmart do, should do, or must do to leverage its position as the largest retailer in the world?"