Does Los Angeles airport go through immigration or customs first?

When foreigners arrive in the United States by plane, they must go through the entry formalities at the airport where they first land, and be inspected by immigration officials and customs officials at the airport. On the one hand, check the qualifications of visitors to the United States, that is, whether they can enter the country; On the other hand, check whether passengers' luggage should pay customs duties or whether there are prohibited items that should be confiscated. 1