My recollection of Van Hollen is that he's pretty ruthless. Maybe not as notoriously savage as someone like Jim Moran, but definitely not a pushover.
She better have her deck of race and gender cards handy, because he'll go after her very hard.
I'd also point out that Maryland just went thumbs-down on a black leftist democrat in the race for governor. Of course, that was an off-year election. I wouldn't bet on that happening in a Presidential year, but one can hope.
Speaking as a resident of the Freak, er Free, State - Van Hollen has carefully cultivated the Dem Congressional leadership and is a favorite in Montgomery County. I’m getting out my popcorn for the P.C. bloodletting on this one. Very, very hard to see a Republican winning this one, but it would sure be nice if a Dan Bongino, etc. ran for this spot. Probably hopeless, but hope springs eternal . . .