I have noticed a striking similarity between the French word chien meaning dog and Russian word щенок "puppy", the both words pronounced exactly the same way except the deminutive suffix -ок in the Russian word.
Initially I thought is was a borrowing from French to Russian. But it turned out not the case.
French chien comes from PIE cu̯ōn "dog"
Russian щенок comes from Proto-Slavic ščenę and is said to be related to Armenian skund, Latin recēns "to start", Greek καινός "new", Indian kániṣṭhas "younger".
This hints that possibly it is the same PIE root, with s-mobile variation.
If they are related, I also wonder, what semantic development is more likely: young->puppy->dog or dog->puppy->young. I think the former.