Fears of a trade war between the U.S. and China continue to escalate as the two countries threaten more tariffs this week. President Trump announces a plan to send National Guard troops to the Mexico border. EPA Administrator Scott Pruitt continues to face backlash in the wake of various ethics scandals. Plus -- Facebook CEO Mark Zuckerberg will testify in Congress following a data breach that affected 87 million users. CBS News Correspondent Steve Dorsey will have these stories and more on the CBS News Weekend Roundup.