The cases themselves can’t be duplicated due to Steam’s backend, but scammers can mimic case names or use inspect URLs that lead to unrelated items. Always double-check the actual trade through the Steam app and confirm the case ID.
https://dmarket.com/cs2-wiki/ helped me figure out how to verify genuine trades, especially when dealing with rare items. I almost accepted a trade that looked clean, but the case was swapped last second. You need to click on each item individually, inspect it, and make sure it's not renamed or switched with something similar. If you’re ever unsure, just walk away.