The ad shows up on Google searches for "Richard Burr." It reads:
Richard Burr NC Senator
Join John McCain's Country First
To Support Candidates Like Burr!
The link goes to a page where McCain notes candidates he is currently supporting: Chris Christie for New Jersey governor, Bob McDonnell for Virginia governor, Henry McMaster for South Carolina attorney general, Rob Portman for Ohio senator, Vaughn Ward for Idaho Congress member, Meg Whitman for California governor, and Burr.
Burr is friends with McCain and campaigned for him in 2008.