“While it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and to focus solely on fulfilling my duties as president for my term,” Mr. Biden posted in a statement on social media.
Unfortunately, it doesn’t look like enough Americans are ready for a black woman as a president for it to happen
Source?
Just a subjective observation
She is pretty closely tracking Biden in match ups against Trump, so it is not clear whether voters are really distinguishing her yet.