This is a Phase II clinical trial for Decitabine plus Camrelizumab resistant/relapsed patients with Hodgkin Lymphoma. The purpose is to evaluate the efficacy and safety of the combination therapy of Chidamide plus Decitabine Plus Camrelizumab.

Inclusion Criteria:

1. Subjects must have histological confirmation of relapsed or refractory Hodgkin lymphoma (HL).
2. 12 to 75 years of age.
3. ECOG performance of less than 2.
4. Life expectancy of at least 3 months.
5. Subjects with lymphoma must have at least one measureable lesion >1 cm as defined by lymphoma response criteria.
6. Subjects must be relapsed or resistant for the treatment of Decitabine plus Camrelizumab. Subjects with autologous hematopoietic stem-cell transplantation are eligible which must be more than 3 months.
7. Subjects must have adequate marrow, live, renal and heart functions.

Exclusion Criteria:

1. Subjects with any autoimmune disease or history of syndrome that requires corticosteroids or immunosuppressive medications.
2. Serious uncontrolled medical disorders or active infections, pulmonary infection especially.
3. Active alimentary tract hemorrhage or history of alimentary tract hemorrhage in one month .
4. Prior organ allograft.
5. Women who are pregnant or breastfeeding.
6. Women with a positive pregnancy test on enrollment or prior to investigational product administration.
7. Subjects who are compulsorily detained for treatment of either a psychiatric or physical (eg, infectious disease) illness.