The primary objective of the phase Ib portion will be to determine the recommended phase II dose of the combination of gemcitabine, cisplatin, plus lenalidomide in patients with advanced/metastatic urothelial carcinoma. The primary objective of the phase II portion will be the progression-free survival at 1 year. The secondary objectives are to evaluate the activity (as determined by objective response rate); and to determine the safety (per the Common Terminology for Adverse Events version 4.0) of combination therapy with gemcitabine, cisplatin plus lenalidomide; to evaluate lenalidomide as maintenance treatment in patients achieving an objective response or stable disease following completion of 6 cycles of combination therapy and; to determine the impact of treatment on peripheral blood immune cell subsets and circulating tumor cells.