Black people, partly.
92% of black voters vote democrat no matter what. Putin could run as Czar of Russia on a democrat ticket and still get 8% of the total American vote because blacks vote democrat. Period. This has been proven time and time again, which is why conservatives are so easily branded "racists" for doing literally nothing racial in politics. Republicans are irrelevant to race, blah blah etc.
The other blacks... I know some black republicans, and among them, three said they were voting against their ideology because it was important enough to see a first black president.
So the identity politics scheme definitely was effective there; I am sure it was prevalent among non-black voters, and it is somewhat a major boon to Trump or a terrible blow to Hillary that all the weight of minority and majesty of her being potentially the first woman president was not enough for the democrats to win in 2016.
Because the identity political vote was tremendous.