Infrastructure delivery has grown increasingly complex as governments seek effective ways to provide large-scale services while managing fiscal burdens and improving implementation efficiency. This study briefly examines how cooperation between the public and private sectors is structured across national contexts, focusing on legal frameworks, financing approaches, institutional capacity, and risk-allocation practices. The research reviews the experiences of Türkiye, the United Kingdom, the United States, China, and Indonesia in implementing infrastructure projects through Public-Private Partnership (PPP) arrangements. These countries represent a mix of major global powers from developed and developing economies, enabling a broader contextual understanding of PPP applications. The analysis draws on a structured review of regulatory conditions, economic environments, and selected project examples in each country, supported by descriptive comparisons of investment patterns and key implementation differences across countries. Given the scope of the study, the discussion highlights representative trends and practical observations rather than providing an exhaustive comparative evaluation. The study also considers the PPP project life cycle, including identification, preparation, procurement, and operation phases, to show how responsibilities are distributed among participating parties. The findings indicate that PPP implementation outcomes vary across countries due to differences in governance structures, regulatory clarity, and institutional effectiveness. While strong legal frameworks and transparent processes contribute to more stable outcomes, challenges such as unclear responsibilities, weak oversight, and financial uncertainty may affect project performance. Overall, PPPs are better understood as governance-based delivery mechanisms rather than purely financial tools.