It really depends, but the rhetoric would be unfavorable in most cases. If he rolls back the Trump tax cuts and returns corporate rates higher it could spell trouble. Those items drove the market favorably. Also, Biden flip flops ( or doesn’t remember) depending on your view. The markets like Trump because they can predict him easier and he is typically pro-business. Biden may be unpredictable, which markets don’t like. You could actually see a slide in early fall if the market feels an uncertain change is coming. In other words, it could be “baked in” a little pre-election. Of course, that assumes the market sees a Biden win, which can be quite different than a current poll.
And this caveat, over the last 5-6 months - the market is unpredictable on its own.
I’m gonna try and get what I can now and go very conservative post Labor Day until the election - unless something becomes very obvious.