According to an editorial, this is a controversial topic: previous studies have suggested increased, decreased, or no association of ACEIs or angiotensin receptor blockers with cancer and lung cancer incidence. It notes that despite the rigorous analytical approach, the study has limitations, including being prone to residual confounding. Information on socioeconomic status was lacking, which may differ in users of ACEIs versus angiotensin receptor blockers. ACEIs became generically available in 1995, whereas the first generic angiotensin receptor blockers were marketed in 2010. Thus socioeconomic differences might have influenced prescribing patterns and lung cancer risk over a long term period. Likewise, residual confounding from other environmental exposures such as radon or asbestos might influence the observed association. Use of ACEIs is associated with a persistent cough, which may have prompted more frequent thorax imaging in ACEI users compared with angiotensin receptor blockers users, but data on such scans was not available in the current analysis. Critically, as different ACEIs have varying pharmacological properties and pleotropic effects, it remains unclear if a particular ACEI drove the observed associations. It adds that this study highlights the value of registry data and a “big data” approach to evaluating long term outcomes, which may be challenging to investigate in clinical trials. It concludes that although a 14% relative increase in lung cancer incidence might not translate to a large absolute risk, the findings are important given the considerable use of ACEIs worldwide, but nonetheless, in an individual patient, concerns about the long term risk of lung cancer should be balanced against gains in life expectancy associated with use of ACEIs. Further studies with long term follow-up are needed to enhance the scientific evidence on the long term safety of these drugs.