The purpose of this trial is to explore the clinical utility of two investigational antibodies in patients with advanced cancer or lymphomas.

This is a multi-center, open-label Phase I/Ib study. The study consists of two dose escalation parts and two dose expansion parts testing GWN323 as a single agent or GWN323 in combination with PDR001. The dose escalation parts will estimate the MTD and/or RDE and test different dosing schedules.

The dose expansion parts of the study will use the MTD/RDE determined in the dose escalation part to assess the activity, safety and tolerability of the investigational products in patients with specific types of cancer and lymphomas.

Approximately 264 adult patients with advanced solid tumors or lymphomas will be enrolled.

Inclusion Criteria:

• Patients with metastatic and/or advanced solid tumors or lymphomas not amenable to curative treatment by surgery.
• Histologically documented advanced or metastatic solid tumors or lymphomas
• Must have a site of disease amenable to biopsy, and be a candidate for tumor biopsy according to the treating institution's guidelines. Patient must be willing to undergo a new tumor biopsy at screening
• ECOG Performance Status ≤ 2.

Exclusion Criteria:

• Presence of symptomatic central nervous system (CNS) metastases, or CNS metastases that require local CNS-directed therapy (such as radiotherapy or surgery).
• Patients diagnosed with T-cell Lymphomas.
• Patients with prior allogenic transplants.
• Patients previously treated with anti-GITR therapy.
• History of severe hypersensitivity reactions to other mAbs.
• Patients intolerant to prior immunotherapy (unable to continue/receive due to immune-related AE).

Other protocol-defined inclusion/exclusion criteria may apply.