Well to his credit Trump thankfully didn't change our engagement in Iraq which continued Obama's slow defeat of ISIS via providing SOF and enablers to the Iraqi Army and the Kurdish Peshmerga. I'm definitely in the camp of people unhappy with the slow Obama approach to ISIS and personally feel more sooner would have been much more appropriate but so long as they are defeated in the end I'm content. The moment Mosul fell we should have been there in a big way to steady the Iraqi government and defeat ISIS instead of letting it drag out for nearly half a decade.
Upon his election I was worried that he'd pull us out of there and Afghanistan as part of his isolationist stance.

Same for the stock market I guess. It's really just a continuation of Obama's policies. The recent tax bill is the only thing that may have an effect that's been done that wasn't just a continuation of present policy. The norm for all Presidents is to claim everything that happens as their personal doing such as his taking personal ownership for the USS Gerald Ford as part of his strengthening the US Military when it was all planned and built under the previous president.