<p>The rapid adoption of Internet of Things (IoT) applications across several domains, including transportation, healthcare, smart homes, and agriculture, has contributed to the concept of smart cities. However, the limited storage and processing capabilities of IoT devices raise a significant concern ensuring secure and reliability-aware solutions in an IoT-driven smart world. Cloud computing has emerged as a potential solution in overcoming the mentioned issue by offering services to IoT applications however, this paradigm is unable to cater latency-sensitive applications. The fog paradigm offers services to such IoT applications by bringing compute, memory and networking capabilities in close proximity to the network edge (data source). This article highlights prominent IoT use case well known as smart healthcare system that utilizes latest established terminology such as Artificial Intelligence (AI), fog computing and Blockchain in order to ameliorate the living standards of societies. The paper discusses about Fog and cloud paradigm impact and proposes an integrated architecture comprising smart multi-layer healthcare system that determines the horizon of IoT applications in the healthcare domain. The proposed conceptual multi-layer architecture addresses key limitations of existing healthcare frameworks by integrating IoT, fog computing, cloud computing, AI, and blockchain to achieve secure, scalable, low-latency, and privacy-preserving healthcare services. Furthermore, the work highlights the role of AI and blockchain technology in the healthcare domain and along with their integrated benefits. Further, the authors rigorously reviewed distinctive techniques and training methods including their objectives, impacts, achievements and limitations. Lastly, simulation tools and future research directions are discussed briefly hoping that this systematic survey works as a stepping stone in healthcare for the new researchers.</p>