Okay, sure. The first place is to immediately dispel the idea that Republicans have ever been about being "pro-business" - and the second place will be that Trump specifically is not.
It's simple Tragedy of the Commons at first. Republicans / Republican Presidents are generally pro-greed and pro-riches, not pro-business, and those are different things. What you want in a good business environment is not achieved with Republican policies. This can be seen with the past few presidents - good economic times and growth with Democrat policies, and poor economic times and decline with Republicans.
Specifics.
> A pro-business politician would raise taxes on the wealthy, provide tax cuts for the middle class, increase the corporate tax rate
Henry Ford is the good example here of showing why this is pro-business. Give your country a stable, wealthy middle class (pay your auto-workers more, a lot more), and then they will be able to buy your products and your company will thrive. Roads will be built for your cars to drive on, with those taxes!
Wealthy people are important in a capitalistic society, but income inequality and extreme wealth present dangers, not useful things. Income inequality will catch up with the business as the middle class fades and doesn't buy their products.
Want a pro-business environment? Increase corporate taxes to fund schools and education and infrastructure so that more people will grow up healthy and wealthy and wanting to buy things.
> Improve immigration so that more people could come in to the country
Is this really a debate, especially here? Most of the smart people in the world who can create wealth and businesses do NOT live in the USA. If they wanted to live here, or did live here, that would be great.
> Address massive business risks like climate change with a serious face
The climate is changing, and it's going to kill a lot of people that could have been buying your products. It's going to displace hundreds of millions of families and settlements. Food production and distribution is going to be wildly affected. Basic things that should be stable in a business environment will not be stable. Climate change is the biggest RISK for corporate profits in the world (though right now you could also see it as an opportunity - if you recognize that it needs to be addressed).
> improve healthcare for everyone in nation
Again is this really a debate? Isn't it obvious that healthy people will be better for business? Do you want your customer base to be dying? Or your employees worried about disease? That's not useful for business.