Cloud computing has revolutionized every field and left no area untouched. The use of cloud-based services is increasing significantly, and so is the rise in cyber threats and attacks targeting cloud environments. An innovative defense mechanism is urgently required, one that goes beyond conventional rule-based security systems to heal and protect cloud infrastructure. This paper draws inspiration from the human immune system and presents the concept of a Cloud Immune System (CIS). This bio-inspired, adaptive, and intelligent cybersecurity framework mimics biological immune responses using Artificial Intelligence (AI) and cloud-native technologies such as AWS SageMaker AI, Amazon GuardDuty, and AWS Lambda etc. This Paper also introduces Data engine, Detection engine, Memory engine and Response Engine which solves security- related issues and keep getting better and better over time. The Cloud immune system autonomously detects anomalies, learns from threats, and responds dynamically to evolving attacks. This paper outlines the theoretical foundation of immune system-based security, maps immune components to AI mechanisms, and presents a scalable architecture for real-world implementation. The proposed model represents a robust defense strategy with the potential to redefine cloud cybersecurity, enhancing resiliency and adaptability against modern cyber threats.