Little or nothing of value. And the debate about whether we should now use those results irrespective of their ethical challenge is moot, because the science is junk. There would be a hideous ethical dilemma had the work in concentration camps been done to a high standard. But it wasn't.
I've not read anything since Berger (1990) which says that there is sufficient scientific "merit" to justify the use of the "data". The letters in response are interesting, too.
Berger, R.L., 1990. Nazi science—the Dachau hypothermia experiments. New England journal of medicine, 322(20), pp.1435-1440.