He began his 2016 presidential campaign with a lie: a false claim that President Obama was not born in America. That "birther" lie was inherently racist: a man of color who lacked an Anglo-Saxon Protestant name could not be a "real" American, notwithstanding Obama was born in Hawaii and thus a natural-born American citizen.
Trump's campaign slogan was inherently racist: Make America Great Again. It was not great under Obama because he was not white. It could be made great again by putting a white man back in the White House, Trump's supporters knew, wink wink.
Indeed, some of his supporters even wore "Put the White Back in the White House" and "Make America White Again" T-shirts at his rallies.
Trump spent much of his presidency trying to trash Obama's legacy: repealing the Affordable Care Act, which he failed to do. Withdrawing America from the Paris Climate Agreement, which never actually happened because of a timed delay built into the enabling legislation. Approving the Keystone Oil Pipeline, which Obama had disapproved and Trump's successor will disapprove again tomorrow.
And on and on.
Trump also failed to erase Obama's legacy in the biggest way: he could not defeat Obama's Vice President, Joe Biden, who tomorrow will become our new President. Nearly everything good about the Obama administration which Trump reversed will simply be reversed back to the way it was once more.