<qa>  What is the effect of pembrolizumab alone or with idelalisThis phase II trial studies how well pembrolizumab alone or with idelalisib or ibrutinib works in treating patients with chronic lymphocytic leukemia or other low-grade B-cell non-Hodgkin lymphomas that have returned after a period of improvement or have not responded to treatment. Monoclonal antibodies, such as pembrolizumab, block cancer growth in different ways by targeting certain cells and allow the immune system to attack the cancer. Idelalisib and ibrutinib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Giving pembrolizumab alone or with idelalisib or ibrutinib may be an effective treatment in patients with chronic lymphocytic leukemia or other low-grade B-cell non-Hodgkin lymphomas. 