The document outlines the proceedings of the 16th international scientific conference 'Strategies XXI', focusing on strategic changes in security and international relations, held on April 9-10, 2020, at the 'Carol I' National Defence University in Bucharest, Romania. It discusses current security challenges due to global events, including the COVID-19 pandemic, and emphasizes the need for comprehensive international cooperation and innovative solutions to address evolving threats. The conference attracted numerous academic papers on diverse topics related to security, with a significant number being accepted for publication.