[vkou]

They weren't the last group, they (along with Unit 731[1][2]) were just the most utterly and unashamedly barbaric group of savages to have done so.

Other groups of people have done plenty of unethical medical experiments since then - also typically against marginalized people.

Take https://en.wikipedia.org/wiki/Chester_M._Southam, for instance - thanks to his contributions to the study of cancer (consisting of injecting cancer cells into people without their consent). Thanks to his, uh, contributions to the field, he was later elected president of the American Association for Cancer Research.

[1] Which is utter nightmare fuel.

[2] Most of the members of which were given immunity from war crimes prosecution by the United States. Utterly mind-blowing. The ones that the communists were fortunate enough to get their hands on were subjected to a helping of Soviet justice.