CPI is most closely related to the exchange rate, because once inflation or deflation occurs, it will be directly reflected in the exchange rate. So we will raise interest rates or cut interest rates to control the gap between exchange rate and GDP. Generally speaking, when the economy is good, the exchange rate will rise, and when the economy is bad, it will lower interest rates and increase liquidity.

Exchange rate is also called foreign exchange market or exchange rate. The ratio of one country's currency to another is the price of one currency to another. Because of the different names and values of currencies in the world, one country's currency should set an exchange rate for other countries' currencies, that is, the exchange rate.