I bought an iPhone in Korea, at the checkout said that in Russia won

Apple stopped sales and services in Russia after Russia's invasion of Ukraine, and the sanctions that followed. Maybe the sales clerk was referring to that.

The sales clerk could also have been referring to the warranty – if you buy an iPhone in one country/region, the warranty isn't good in another country/region. Or to the phone's cellular or Wi-Fi frequency coverage – as that could also vary somewhat depending on the country/region variant.

You may want to go back to the place where you bought the iPhone and ask them what they meant.