Melanoma is the most serious type of skin cancer, affecting nearly 54,000 people in the United States each year. Melanomas often develop in pre-existing moles or as new moles on the body. If left untreated, the cancerous cells can spread throughout the body. Fortunately, melanoma can be cured if a person is diagnosed and treated early. Typical treatments include surgery, amputation, chemotherapy, and immunotherapy. Interleukin-2 (IL-2) treatment, a type of immunotherapy, uses the body's immune system to slow or stop the spread of cancer cells to other parts of the body. However, IL-2 treatment is typically associated with severe side effects, including depression, fatigue, and difficulty thinking. This study will evaluate whether escitalopram, an antidepressant, can help improve treatment-related depressive symptoms, reduce stress hormone levels, and increase the number of treatment cycles among people with metastatic melanoma who are receiving IL-2 treatment.