The rapid proliferation of digital infrastructures, including cloud computing, the Internet of Things (IoT), and artificial intelligence (AI), has transformed the landscape of cybersecurity, introducing both new opportunities and heightened risks. This paper presents a comprehensive literature review of cybersecurity advancements between 2020 and 2024, focusing on the integration of AI and machine learning to address evolving threats. Thirty academic studies were analyzed to explore key themes, including the role of AI in threat detection, the security challenges posed by IoT, and the impact of generative AI technologies. AI and machine learning have demonstrated remarkable potential in improving cybersecurity frameworks, particularly through predictive models that enhance threat detection and reduce false positives. Generative AI, while presenting significant opportunities for defence, also poses new risks such as phishing, social engineering, and automated hacking, requiring sophisticated mitigation strategies. Similarly, the growing reliance on IoT devices, especially in industrial systems, has introduced vulnerabilities in communication and management protocols, which AI-driven solutions like federated learning aim to address by providing decentralized cybersecurity without compromising privacy. In addition, emerging trends such as cyber threat intelligence (CTI) mining have positioned organizations to adopt proactive defence strategies by identifying threats in real time. Despite these advancements, significant challenges remain, particularly around the ethical implementation of AI in cybersecurity and the need for standardized frameworks capable of addressing both current and future threats. The findings of this review emphasize the critical role of AI in shaping the future of cybersecurity while highlighting the importance of robust ethical standards and regulatory frameworks to mitigate the risks associated with advanced technologies like AI and IoT. Future research should prioritize the development of AI-driven cybersecurity solutions that are both effective and ethically sound.