Abstract: The high rate of change in cloud computing and digital transformation has brought new challenges on cybersecurity, which has rendered perimeter-based security models to be irrelevant. In this paper, the adoption of Zero-Trust Architecture (ZTA) as a core strategy in the securing of the large scale cloud infrastructure is discussed. The combination of least privilege, continuous authentication, and dynamic access control principles in Zero-Trust provides a powerful security framework that can be employed to minimize the emerging threats. We review the existing literature and the case studies through a thorough review of the literature and case studies to determine whether the concept of Zero-Trust can be utilized to improve the security of multi-cloud and hybrid cloud environments. The paper also explains how AI and machine learning can be combined to strengthen Zero-Trust principles to offer adaptive threat detection and response functionality. This study underlines the practical importance of ZTA to the organizations that are going through digital transformation and provides information about the best practices, implementation plans, and quantifiable results in cloud security. The research ends with the recommendations that can be given to businesses that wish to integrate Zero-Trust architecture into their long-term cybersecurity strategy.