Alterations in cognitive/affective functioning are among the most challenging adverse effects experienced by 80% of patients with metastatic melanoma and metastatic renal cell carcinoma undergoing high-dose interleukin 2 (IL-2) therapy.The purpose of this literature review is to describe what is known about IL-2-induced cognitive/affective symptoms, their prevalence, and level of severity and synthesize findings to determine areas for future research to address symptom management challenges. This review describes the IL-2 patient experience and the pathophysiology leading to these changes.An online electronic search using PubMed was performed to identify relevant literature published between 1992 and 2015. Of the original 113 articles, information was extracted from 9 articles regarding cognitive symptoms, affective symptoms, sample size, research design, reliability, and validity.Our review suggests that the trajectories, breadth, and depth of cognitive/affective symptoms have yet to be described. Despite intervention studies designed to address the psychosocial complications of IL-2, an understanding of the level of altered cognitive/affective symptoms experienced by IL-2 patients remains unclear.Our literature review reveals a lack of standardization when assessing, reporting, and managing cognitive/affective symptoms. Patients/family members have reported cognitive/affective symptoms to be the most alarming and difficult symptoms, yet these symptoms are not adequately screened for, and patients were not informed about potential changes.Assessing patients for cognitive/affective alterations is important to reduce anxiety while improving outcomes. Education about the illness trajectory (what to expect during/after treatment) can help care partners/patients set realistic shared expectations and increase coping.