See this section of the FAQ. A few of the experiments provided datasets we wouldn't have otherwise--stuff like how long it takes for people to die of dehydration, or low air pressure, or hypothermia.

But the actual medical experiments were mostly useless. Some of them were just doctors thinking of ways to torture people. Even when there was an actual experimental aim, some of them were based on pseudoscience, and couldn't possibly have achieved anything. Of the ones that were actually experiments involving actual science, the methodology was usually so poor that nothing of value could've been found.

So while some of the data is used today, most of it isn't the sort you'd say is "affecting modern medicine". The TB experiments or wound infection experiments didn't change how we treat these things today, for instance.