Background and Summary: Thanks to increasing cure rates to currently >80%, children, adolescents, and young adults (CAYA) survive their cancer much more frequently today than decades ago. Due to their long life expectancy, CAYA cancer survivors are at a particular risk of long-term sequelae from the cancer itself or the therapy applied; this requires specific follow-up, and preventative or even therapeutic interventions. Thus, compared to the normal population, morbidity and mortality may be significantly increased. In 2 of 3 survivors, the cancer and the respective treatment can lead to late effects, even after 30 years, which require specific therapy; in about one-third of these cases, these effects are classed as severe. Applying structured follow-up could identify these late effects at an early stage and initiate immediate treatment. In 2018, a working group dealing with long-term survival after cancer detected <40 years of age was founded within the framework of the National Cancer Plan of the German Federal Ministry of Health.