RATIONALE: Monoclonal antibodies, such as tremelimumab and CD40 agonist monoclonal antibody CP-870,893, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry cancer-killing substances to them. Giving tremelimumab together with CD 40 agonist monoclonal antibody CP-870, 893 may kill more tumor cells.