Observational studies are of paramount importance to enhance knowledge in medicine and oncology. The choice of methodology and analytic approach will influence the inferences we make as well as their correctness. This case study will provide insight on how to emulate a target trial using observational data, and why that is preferable to several other conventional methods in terms of causal inferences. It will also address the importance of recognizing and avoiding immortal-time bias at all occasions. The case applies the method to the clinical research question whether initiation of statins improves cancer survival but similar methodology can be applied to essentially all clinical research questions as long as you can specify a target trial.