Use of surrogates as primary endpoints is commonplace in hematology/oncology clinical trials. As opposed to prognostic markers, surrogates are endpoints that can be measured early and yet can still capture the full effect of treatment, as it would be captured by the true outcome (e.g., overall survival). We discuss the level of evidence of the most commonly used endpoints in hematology and share recommendations on how to apply and evaluate surrogate endpoints in research and clinical …