Humanity has fantasized about artificial intelligence tools able to discuss with human beings fluently for decades.Numerous efforts have been proposed ranging from ELIZA to the modern vocal assistants.Despite the large inter-est in this research and innovation field,there is a lack of common understanding on the concept of conversational agents and general over expectations that hide the current limitations of existing solutions.This work proposes a literature re-view on the subject with a focus on the most promising type of conversational agents that are powered on top of knowl-edge bases and that can offer the ground knowledge to hold conversation autonomously on different topics.We describe a conceptual architecture to define the knowledge-enhanced conversational agents and investigate different domains of appli-cations.We conclude this work by listing some promising research pathways for future work.