The Software Development Lifecycle (SDLC) is a structured methodology that outlines a series of phases for developing high-quality software efficiently and cost-effectively, from planning to long-term maintenance. It provides a flexible framework that can be adapted to specific project needs, helping teams manage costs, deadlines, and capabilities while maintaining high standards. The SDLC consists of five key phases: Planning, Implementation, Testing, Deployment, and Maintenance, each setting the stage for the next and aimed at minimizing technical debt. The integration of Continuous Integration and Continuous Delivery (CI/CD) enhances the SDLC by automating testing, building, and deploying processes, thus improving code quality, delivery speed, and developer productivity. Challenges in implementing the SDLC often arise from poor communication and shifting requirements during the planning phase, emphasizing the importance of clear goal-setting and comprehensive testing. A well-defined SDLC, complemented by CI/CD practices, not only enhances project management and risk mitigation but also leads to higher customer satisfaction and enhanced security by proactively addressing potential vulnerabilities throughout the development process.