It’s amazing how often “science” changes. Back in June 2015, there was a news article which stated that scientists had shown that Neanderthals and homo sapiens had interbred 50,000-60,000 years ago, which effectively meant that Neanderthals are human. Now they’re saying the interbreeding happened more like 100,000 years ago.
Based on the Bible, I would say that there is no meaningful difference between Neanderthals and homo sapiens. If they can breed, then they’re the same “kind”. Humans were created on day 6 of the Creation Week (Genesis 1:27). I think the differences from Neanderthals and other humans are just genetic traits which began to take shape after the Tower of Babel (Genesis 11:1-9), when humans were grouped by language, effectively narrowing the gene pool for those groups and giving them common physical traits. But what do I know?