Inclusion Criteria:
* main inclusion:
1. Tumor types and prior antitumor therapy: Phase Ib:Dose Escalation: All enrolled patients must have histologically confirmed diagnosis NHL who have received at least one line of prior systematic treatment (and ≤ 5 lines) and relapses or refractory. Phase Ib dose expansion part: All enrolled patients must have histologically confirmed diagnosis of PTCL, including subtypes: PTCL-NOS, AITL, ALK + ALCL, ALK-ALCL, NKTCL, enteropathy associated T-cell lymphoma (EATL), monomorphic epitheliotropic internal T-cell lymphoma (MEITL), Hepatosplenic T-cell lymphoma (HSTCL), follicular T-cell lymphoma (FTCL), Nodal peripheral T-cell lymphoma with TFH phenotype (Nodal PTCL-TFH) and other invasive T-cell sources NHL at the investigator and sponsor's discretion (except highly invasive). All enrolled patients had relapsed or refractory diseases after receiving 1-line systematic treatment (≤ 3 lines). Phase II: All enrolled patients must have histologically confirmed diagnosis of PTCL, including subtypes: PTCL-NOS, AITL, ALK+ALCL, ALK-ALCL, NKTCL, EATL, MEITL, HSTCL, FTCL, Nodal PTCL-TFH et al. Patients must have histologically confirmed diagnosis of R/R PTCL who have received at least one line of prior systematic combination chemotherapy and at least one new drug therapy (prior antitumor treatment lines ≤4 lines) : relapse and/or refractory.
2. Availability of qualified tissue samples by patient for pathological diagnosis by the central laboratory.
3. The Eastern cooperative oncology group (ECOG) score 0-1.
4. Life expectancy ≥ 3 months before starting HH2853 treatment.
5. Sufficient bone marrow, liver and renal functions.
Exclusion Criteria:
* main criteria:
1. Previous treatment with EZH2 or EZH1/2 inhibitors.
2. Central nervous system invasion.
3. Any previous history of bone marrow malignancy, including myelodysplastic syndrome (MDS).
4. Received medications that are known potent CYP3A4 inducers/inhibitors within 1 week prior to first dose.
