What does illegal immigration in Mexico mean?

Mexicans who entered the United States illegally or legally with non-immigrant visas but failed to integrate after the permanent residence period in the United States. According to the original documents of the inquiry, Mexican illegal immigrants refer to Mexicans who entered the United States illegally or legally with non-immigrant visas, but failed to integrate into the United States after the deadline, and are the main body of illegal immigrants in the United States. Illegal immigrants refer to undocumented immigrants who cross the border illegally by non-citizens.