The article is very skimpy on the details, but it is worth mentioning that this is not the first time Siberian languages have been linked to indigenous North American languages.

Na-Dene and Yeniseian languages are theorized to be part of a common family and the evidence is pretty good; they come respectively from America and Siberia. See https://www.science.org/content/article/land-bridge-connects... for some more information.