 I. To compare the time-to-tumor progression, progression-free survival and overall survival of patients with metastatic RCC treated with high dose aldesleukin combined with entinostat to the historical data of patients treated with high dose aldesleukin alone. Phase II II. To assess the toxicity of high dose aldesleukin combined with entinostat. Phase II III. To evaluate entinostat pharmacodynamics PD in blood and tumor samples. Phase II IV. To measure the association between baseline laboratory parameters e.g. cluster of differentiation CD4, CD8, CD4forkhead box P3 Foxp3, tumor blood metabolism, and a variety of response variables e.g. toxicity, response and survival. Phase II V. To explore the relationship between entinostat exposure with PD endpoints e.g. toxicity and histone acetylation in peripheral blood mononuclear cells or peripheral blood mononuclear cells PBMNCs and changes in T cell subset population. Phase II VI. To evaluate the modulation of tumor metabolism by fluorodeoxyglucose FDG, fludeoxyglucose F 18 positron emission tomography PETcomputed tomography CT scan. Phase II 