Kamala loses the election, but Joe Biden dies before January. She has to be president for like, 3 weeks, before handing over the whitehouse to Trump. Hillary Clinton has an aneurysm due to jealousy and rage
In that 3 weeks Kamala could do something cool, and it would have Presidential immunity, but we all know that a Dem would be too chicken shit to ever wield that power.
Biden kicks it in early January, giving us 2-3 weeks of Kamala before handing the reins over to Trump. Years of Big Macs and Diet Cokes finally takes it toll and Trump dies in the ensuing months, leading to Vance taking the White House. Year of Four Presidents.
Even funnier if some Qanon adventure seeker got it into his head Vance is part of the Deep State and had Trump eliminated. So then we have a fifth president after Vance.