Trump nominated Gen. James Mattis for Secretary of Defense. The only problem with that nomination for Trump is that
To take the job, Mattis will need Congress to pass new legislation to bypass a federal law that states secretaries of defense must not have been on active duty in the previous seven years. Congress has granted a similar exception just once, when Gen. George C. Marshall was appointed to the job in 1950.
To get through a potential Senate filibuster, Trump will need Democratic votes. The price for such bipartisanship, should be a little bipartisanship from Trump and McConnell--confirming Merrick Garland as Supreme Court Justice.