A more thorough explanation:

United States Citizenship and Immigration Services (USCIS) is a government agency that processes immigration applications in the United States. It is part of the Department of Homeland Security.

USCIS evaluates a person’s eligibility for:

• Citizenship
• Naturalization
• Immigration based on familial status
• Permanent residency status
• Visa extensions
• Humanitarian aid

USCIS also plays a major role in evaluating eligibility for asylum and work visas that involves other agencies and immigration courts.

For example, USCIS, the Department of Labor, and the Bureau of Consular Affairs all play a role in granting H-1B visas.

However, USCIS is known for having a backlog of applications and cases, which means that a person may have to wait a year or longer before having determinations on their immigration status for certain kinds of applications.

Compare with Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP).

Example: John is a citizen of Canada who wants to move to the United States to work. He applies for an H-1B visa through USCIS, which evaluates his eligibility based on his qualifications and the needs of his potential employer. If USCIS approves his application, John can then apply for a work visa and move to the United States.

Example: Maria is a refugee from El Salvador who is seeking asylum in the United States. She applies for asylum through USCIS, which evaluates her eligibility based on the persecution she faced in her home country. If USCIS approves her application, Maria can then apply for a work permit and begin rebuilding her life in the United States.

These examples illustrate how USCIS evaluates eligibility for different types of immigration applications and plays a crucial role in determining a person's immigration status in the United States.