International students and scholars have long been central to the academic, economic, scientific, and internationalization missions of U.S. higher education. The United States has historically benefited from attracting educated individuals who contribute to research, innovation, entrepreneurship, institutional diversity, and the national scientific workforce. However, an increasingly complex and restrictive immigration environment has created uncertainty regarding international students’ and scholars’ ability to enter the United States, pursue education, conduct research, obtain practical training, travel internationally, and transition into the U.S. workforce. This integrative literature review examines the effects of contemporary U.S. immigration policies and administrative restrictions on international students and scholars and considers their implications for U.S. higher education, institutional internationalization, and global competition for talent. Drawing on interdisciplinary scholarship and policy literature, the review synthesizes evidence concerning visa policies, immigration restrictions, employment and training regulations, travel requirements, and changing federal administrative practices. Findings indicate that heightened uncertainty and restrictive policies can negatively affect educational experiences, career planning, institutional engagement, recruitment decisions, and willingness to pursue long-term opportunities in the United States. These developments may also influence enrollment, research productivity, international partnerships, and the nation’s ability to attract and retain global talent. The review further considers whether current policies may contribute to a shift from “brain gain” toward “brain drain” by encouraging educated international students and scholars to pursue opportunities in competing destinations. Implications for policymakers and higher education institutions emphasize predictable, transparent, and internationally competitive immigration policies that support academic mobility, innovation, and U.S. leadership in global higher education.