Pembrolizumab and Interferon Gamma-1b in Treating Patients With Stage IB-IVB Relapsed or Refractory Mycosis Fungoides and Sezary Syndrome

This phase II trial studies how well pembrolizumab and interferon gamma-1b work in treating patients with stage IB-IVB mycosis fungoides and sezary syndrome that has come back or has not responded to previous treatment. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Interferon gamma-1b may boost the immune system activity. Giving pembrolizumab and interferon gamma-1b together may work better in treating patients with stage IB-IVB mycosis fungoides and sezary syndrome.