As reported in an MNB Breaking News alert yesterday, Walmart announced that Mike Duke, 63, is retiring from his job as CEO of the company, and will be succeeded by Doug McMillon, 47, who has been running Walmart's international business. The change is scheduled to take place in February 1. McMillon will be just the fifth CEO of the company founded by Sam Walton since it went public in 1970. Some analysis of the leadership changes…. • Bloomberg Businessweek : "McMillon has some well-chronicled challenges to address, from an increasingly competitive retail landscape to the collateral damage of bribery allegations in Mexico. That could mean he starts out playing defense. Let's hope not. McMillon has an even bigger opportunity to build on Wal-Mart's strengths. To do that, he needs to foster a different mindset in Bentonville and focus more sharply on a few areas. The biggest and most pressing challenge: figuring out how to win online. "The world's largest retailer has an underwhelming record on the digital front.