It's a presidential tradition to grant pardons to federal prisoners just before the President leaves his office. Who do you think deserves a 2017 Presidential Pardon? Leonard Peltier? Someone else? No one at all?
The people in jail under Marijuana possession in all 50 states, or especially in states where it is legal currently, or even just people convicted after the bill was passed but before it was legal. They are a waste of tax money.