One outcome which may happen is not much changes at all. A status quo election which both sides might not be happy with although supporters of the President might feel relief that there wont be any impeachment movement.
If the Senate stays unchanged it's actually pretty bad news. They'll have no margin to get anything passed or judges approved if one RINO defects (like it is currently).
A second reason no net change in the Senate is bad news is that the map this year is favorable to the Republicans. Logically the GOP should be able to gain 4-5 seats, based on the states electing Senators. It will be much less favorable in 2020. Therefore no net change means it's virtually certain the Senate goes Democrat in 2020, even if Trump gets reelected. Even a net gain of a couple of seats, which is far from certain, probably means the Dems have a better than 50% chance of gaining control in 2020.
If the GOP retains a majority in the House by a razor thin margin, they will effectively lose control of it. The RINOs will vote with the Dems most of the time. If Jordan is chosen by the GOP caucus to be their new leader, I expect some RINO's will refuse to vote for him. Some of them might vote to impeach as well.