requiring first aid, related education and implementation strategies, and systems of care. After the publication of the 2015 International Consensus on CPR and ECC Science With Treatment Recommendations, ILCOR also committed to sponsoring a continuous evidenceevaluation process, with topics prioritized for review by the task forces and with CoSTR updates published annually. For this 2020 CoSTR, the 6 ILCOR task forces performed structured reviews of 184 topics, completing the most ambitious evidence review that ILCOR has attempted to date.The ILCOR systematic review process continues to be based on the methodological principles published by the National Academy of Health and Medicine (formerly the Institute of Medicine) 2 ; Cochrane 3,4 ; Grading of Recommendations Assessment, Development, and Evaluation (GRADE) 5 ; and the reporting guidelines based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations. 6,7 Three types of evidence evaluation provided the basis for this 2020 CoSTR: the systematic review, the scoping review, and the evidence update. Based on recommendations from the ILCOR Scientific Affairs Committee and agreement of the task forces, only systematic reviews could result in new or modified treatment recommendations.