I don't think Biden is going to be their pick in the end. I think they are waiting until later to reveal their choice. Think about it, if they bring out their candidate now it's easy to scrutinize and pick apart everything about them. If they bring her out later (guessing it's a her) then we'd have months to expose her and that's too much scrutiny. Plus Biden is a child sniffing old white cis male, they're just using him as a temporary punching bag to take all of the summer punches leading up to the election. It's going to be a female minority who gets picked, they are too predictable.