Scholarly publishing is like a conversation between researchers and critics with the purpose of advancing knowledge in a field.
When you read a scholarly article or conference paper, you are participating as a listener in that conversation. Once you have identified a gap in the literature that you can contribute to, you may take your turn in the conversation by sharing your own research which, in turn, will be built upon by others.
The conversation started long before you came to the university, and it will continue with no end as long as there is interest (and sometimes funding) to pursue knowledge in that field.
Credit: University of Minnesota Libraries
A literature review is how you demonstrate your familiarity with the conversation happening in your research area and how you position your own research as building on prior works to contribute something new to the conversation.
A scholarly conversation is formally represented in the citations in published literature. By referring to prior works, you can get an understanding of how a researcher's contribution built on those works. Further, by reviewing works derived from that researcher's contribution, you can better understand its impact.
A tool like Connected Papers allows you to visualize the conversation as a knowledge graph. By exploring the nodes in the graph, you are able to explore the conversation visually.