Inclusion Criteria:

- Previously received the following lines of systemic therapy for the
advanced/metastatic disease:

- Gastric cancer: at least 2 lines of therapy

- Renal cell carcinoma: at least 2 lines of therapy

- Melanoma:

- BRAF V600E mutant: must have received at least 2 lines of therapy

- BRAF V600E wild type: must have received at least 1 line of therapy

- Sarcoma: at least 1 line of therapy

- Testicular germ cell tumor: at least 2 lines of therapy

- Cervical cancer: at least 2 lines of therapy

- Mesothelioma: at least 2 lines of therapy

- Non-small cell lung cancer: at least 3 lines of therapy

- Head and neck squamous cell carcinoma: at least 2 lines of therapy

- Suitable site to biopsy at pre-treatment and on-treatment

- Measurable disease as determined by Response Evaluation Criteria in Solid Tumors
(RECIST) 1.1 or modified RECIST (mRECIST) for mesothelioma

- Eastern Cooperative Oncology Group performance status of 0 or 1

Exclusion Criteria:

- Systemic anti-cancer therapy within 2 weeks prior to start of study drug

- For soft tissue sarcoma and testicular germ cell tumor patients only: prior immune
therapy

- Therapeutic radiation therapy within the past 2 weeks

- Prior exposure to agents targeting the Tumor Necrosis Factor Receptor type 2 (TNFR2)
receptor

- Active autoimmune disease requiring systemic treatment in the previous 2 years

- Systemic steroid therapy (>10 mg/day of prednisone or equivalent) or any immune
suppressive therapy

- Persisting toxicity of ≥Grade 2 (≥Grade 1 for diarrhea) relating to prior anti cancer
therapy with the following exceptions:

- All grades of alopecia are acceptable

- Endocrine dysfunction on replacement therapy is acceptable

- Severe or unstable medical condition, including uncontrolled diabetes, coagulopathy,
or unstable psychiatric condition

- Major surgery within 2 weeks of the first dose of study drug

- History or presence of drug or non-drug induced interstitial lung disease or
pneumonitis ≥Grade 2

- History of allergic reactions, immune related reactions, or cytokine release syndrome
(CRS) attributed to compounds of similar chemical or biologic composition to
monoclonal antibodies or any excipient of HFB200301

- Using sensitive substrates of major cytochrome P450 (CYP450) enzymes

- Known active malignancy, with the exception of the specific cancer under investigation
in this trial, that required treatment within the previous 2 years

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Eligibility last updated 11/15/22. Questions regarding updates should be directed to the study team contact.