This review discusses the theoretical frameworks and application prospects of Zero Trust Security (ZTS) in cloud computing context. This is because, as organisations move more of their applications and data to the cloud, the old borders-based security model that many implemented are inadequate, therefore a model that has a trust no one, verify everything approach is required. This paper analyzes the core principles of ZTS, including micro-segmentation, least privileged access, and continuous monitoring, while critically examining four major controversies: scalability issues, Economics, Integration issues with existing systems, and Compliance to legal requirements. In this paper, having reviewed the existing literature in the field and various implementation cases, the main barriers to implementing zero trust security were outlined, including the dimensions of decreased performance in large-scale production and the need for major upfront investments that can be difficult for small companies to meet effectively. This research shows that there is no clear correlation between security effectiveness and operational efficiency: while organisations experience up to 40% decrease of security incidents after implementation, they note first negative impacts on performance. This study also shows that to support ZTS there is a need to address the context as the economics and operations of ZTS differ in strengths depending on the size of the organizations and the infrastructures. Some of these are: performance enhancement and optimizations, economic optimization, architectural blend, and privacy-preserving technologies. This review enriches the existing literature on cloud security by presenting both the theoretical framework of ZTS and the observed issues, and provides suggestions useful for future research and practice in the construction of the cloud security architecture.