It is hard to follow rules about sanctions from the US government. Many companies are still trying to understand which products and services are not allowed and what actions would break the rules. Here is an example:
A US company wants to work with a company in Russia. But the Russian company is on a list of companies that the US government does not allow American companies to do business with. The US company needs to ask for permission from the government before they can start working with the Russian company.
A US company tries to order something from a supplier in Russia that they have worked with for a long time. But **what sanctions are on Russia from US?** The supplier is not on the list of companies that the US government does not allow American companies to do business with. But the bank that the supplier uses is on the list. The US company might need to find a different way to pay for the goods, like using a bank in the US.
A US company wants to work with a company in China. The Chinese company is not on the list of companies that the US government does not allow American companies to do business with. But the US company knows that the Chinese company works with a company in Russia that is on the list. The US company needs to make sure they do not accidentally do business with the Russian company through the Chinese company.
One example of a product that is challenging is a smartphone. The smartphone might have parts made in different countries, like the screen from Korea and the processor from Taiwan. It might also have materials from different places, like minerals from Africa and plastics from Asia. The company that makes the smartphone needs to make sure they are following all the rules about sanctions and other regulations for every country and material involved in the supply chain.