Ruxolitinib Phosphate to Treat Diffuse Large B-Cell or Peripheral T-Cell Non-Hodgkin Lymphoma After Stem Cell Transplant

Inclusion Criteria: * Subjects must have histologically documented relapsed or refractory disease, with a diagnosis of one of the following lymphoid malignancies: diffuse large B-cell lymphoma, peripheral T-cell lymphoma (any subtype); subjects must have received at least one prior systemic chemotherapy and must have either received an autologous stem cell transplant, refused or been deemed ineligible for an autologous stem cell transplant * Subjects must be willing and able to have a fresh tumor biopsy prior to start of study treatment for research evaluations and cohort categorizing; Note: if insufficient fresh tissue is obtained to provide sub-classification for cohorts, then tissue material from a previous relapse biopsy and/or original diagnostic block may be requested to meet this criterion * Subjects must have measurable lesions (at least one target lesion measuring 2 cm in diameter) by computerized tomography (CT) scan, and/or measurable lymphoma cutaneous lesions of any size * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * Absolute neutrophil count (ANC) \>= 1,000/mm\^3 * Platelet count \>= 75,000/mm\^3 * Hemoglobin \>= 8.0 g/dL * Serum creatinine =\< 2.0 g/dL or calculated creatinine clearance \>= 60 mL/min (Cockcroft-Gault method) * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) =\< 2.5 x institutional upper limit of normal (ULN) or =\< 5 x ULN if liver involved by lymphoma * Bilirubin \< 2.0 x ULN unless subject has Gilber…