On immigration overall...
It's going to get "worse." Regardless of who is in the White House.
We are rendering the equatorial regions uninhabitable. People who live in those regions are going to migrate toward the temperate regions, north and south.
Nations in temperate regions (Canada, the US; Europe; Russia; China; Chile, Argentina; South Africa, Zimbabwe; Australia) are going to have to decide how they deal with this, because as the equatorial regions get hotter and hotter, large chunks of the populations there are going to begin to migrate. (Their only option will be to stay and die.)
The history, and pre-history, of humanity suggests that the way populations in one region will deal with large migrations from other regions is... well, wholesale slaughter. For most of our time on this planet, human populations were relatively small, and while the slaughter decimated both a migratory population and the population of the area they were entering, the absolute numbers (in modern terms) tended to be small. Given our current population of about 8 billion...oy.
We tend to look at the "immigration problem" in short-term, localised ways. But this is a longer-term, global issue, driven by what we have done, and are continuing to do to the climate.
Americans... well, we're not the saintly exceptional people we like to think we are. That's why millions of us have no issue with Greg Abbott installing buoys stretched with razor wire in the Rio Grande, whose purpose is to maim those trying to cross, and ensure that they die by drowning. That's why millions of us would be fine with an impenetrable barrier beyond which desperate people would starve and die - or with armed men picking off those who found a way past the barriers.
Now, that's not all Americans. But 60-70 million of us are going to go out and vote for Trump/Vance in November - either knowing where those people stand on how to deal with immigrants (and not caring, or seeing mass human suffering as acceptable "collateral damage"), or else just ignorant, and voting for the "brilliant businessman" as seen on The Apprentice.
Donald Trump: "I'm not a human being, but I played on on TV."