Can any Native American society make contact with the Old World? My TL is stalled at the minute because I'm unclear if, say a Tingit>Ezochi contact can occur. I'm Imagining the Tingit establishing contact but as that didn't happen OTL I Imagine there's some reason it didn't?
It's a very long journey from the Tlingit homeland to even the closest parts of Siberia, let alone Ainu lands. You'd need them to have a more maritime (even more than OTL) and some real demographic advantages (which probably comes with that, since more/better seafaring equals more fishing resources, more sealing, and perhaps whaling too).
The main Old World-New World trade there was sporadic contact between the Yupiks and Inuit across the Bering Strait. Iron goods occasionally crossed to the New World this way. The Tlingits were in contact with the Yupiks, they thought them as primitive (the exonym in Tlingit means "bone in the nose" and is just as dismissive/derogatory as that phrase is in English), but still treated them as useful trading partners. They valued them as a source of walrus ivory.
Basically you need the Tlingits to become the "Taino of Alaska" so to speak, and to do so they'd probably need sails (from reeds or Indian hemp, the former attested OTL in the PNW but was inspired from European ships) or otherwise serious innovations in their shipbuilding. In this case, I think they absolutely could contact the Old World given enough time (although Hokkaido is a serious stretch, Kamchatka would be doable) but their culture would fundamentally change, especially those who'd inevitably settle in the harsh lands of the Aleutians.