"A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a specific research question. Researchers conducting systematic reviews use explicit, systematic methods that are selected with a view aimed at minimizing bias, to produce more reliable findings to inform decision making" (Cochrane Collaboration, 2022).
The following books provide a good introduction to those new to conducting a systematic review:
Cochrane Handbook for Systematic Reviews of Interventions by 
How to Perform a Systematic Literature Review : A Guide for Healthcare Researchers, Practitioners and Students by