At just the very highest levels (people with more than 5 million dollars in wealth), there is currently an inheritance tax that was set up for the purpose of lessening the grip of “power” families that essentially become a perpetual un-elected ruling class. Of course, Trump wants to get rid of this because it affects his family. And, when he chants “we’re going to get rid of the death tax!”, that’s exactly what he is talking about – ensuring his ancestors continue to have power over yours.
God, the way the Republicans frame that is so slimy, but they know exactly what they’re doing. Death Tax sounds so ominous, people’s minds instantly go to “oh, they tax people for dying? that’s horrible!” but that’s not what it is.