Pence might, perhaps, have some small influence if Trump is confirmed as the candidate, which seems highly likely, legal jeopardies permitting.

Pence has to base his pitch on the dangerous and immoral conduct of Trump, as witnessed from the inside. He has to spend the next few months trying to rally his base (religious fanatics) around the idea that Trump is so repugnantly evil and flawed that even if he gives them anti-abortion supreme court judges or whatever else they want from 'their' president, it is their moral and patriotic duty not to vote for him.

That won't work in the primaries, but it will mean that Pence's anti-Trump message is repeated over and again and given airtime, which wouldn't happen if he weren't on the stump. Let's face it, who would give Pence airtime otherwise?

And come the Biden v. Trump showdown, that repetition (and any insider evidence he may choose to reveal) might have persuaded some both extreme and more moderate evaneglists et al. that this time, they should abstain, for their God's sake. That could make the difference in some swing states.

It's also worth pointing out that as VP, it was in Pence's personal political interests to keep schtum about Trump's outrages. Now the opposite is true.