Every year more patients with solid or hematological tumors are admitted to the intensive care units. The improvement in the pathophysiological understanding of this group of patients and the increasingly better and more targeted treatment options for their underlying disease have led to a significant increase in their survival over the past two decades. We are living in an era in which we are defining the standards that offer the best way to care for them: from the organization and running of ICUs, the definition of clear admission criteria from the available evidence, and the development of new admission policies that expand the classic dichotomous view of whether or not they are candidates for admission to ICUs to analyzing the best treatment for them, avoiding excessive treatment, and, above all, respecting their principle of autonomy.