Rule 90.703 Opinion on ultimate issue

An expert or other witness can give an opinion about the most important question in a case, even if that question is the exact thing the judge or jury needs to decide.

For example, a medical expert can say "in my opinion, the defendant's actions caused the injury" even though causation is the central issue the jury must rule on. The opposing side cannot block that testimony just because it touches on the final question in the case.