This randomized phase II trial is studying sorafenib and interferon alfa-2b to see how well they work compared to sorafenib alone in treating patients with metastatic kidney cancer. Sorafenib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Interferon alfa-2b may interfere with the growth of tumor cells. Sorafenib and interferon alfa-2b may also block blood flow to the tumor. Giving sorafenib together with interferon alfa-2b may kill more tumor cells.