<qa>  What do monoclonal antibodies do to block cancer growth?This phase III trial studies the side effects and the best dose of veliparib when given together with bendamustine hydrochloride and rituximab and to see how well they work in treating patients with lymphoma, multiple myeloma, or solid tumors that have come back or have not responded to treatment. Veliparib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as bendamustine hydrochloride, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as rituximab, can block cancer growth in different ways. Some find cancer cells and help kill them or carry cancer-killing substances to them. Others interfere with the ability of cancer cells to grow and spread. Giving veliparib together with bendamustine hydrochloride and rituximab may kill more cancer cells. 