The writ of mandamus has been pivotal in several landmark cases within immigration law. Notably, it has been invoked to compel action from government agencies when they fail to perform a duty required by law. One famous case involving the writ of mandamus is Chen v. USCIS, where the court ordered the United States Citizenship and Immigration Services (USCIS) to process a backlog of naturalization applications within a specified timeframe. This case underscored the importance of timely adjudication of immigration matters and highlighted the role of the judiciary in holding agencies accountable. Additionally, Matter of Wang, another significant case, established that mandamus relief could be sought to challenge unreasonable delays in visa processing. These cases demonstrate how the writ of mandamus serves as a legal recourse for immigrants and their advocates when facing administrative obstacles in the immigration system.