A Phase 1/2a, Open-Label, Dose Escalation and Expansion Study of the Safety and Tolerability of T3011 Administered Via Intratumoral Injection as a Single Agent and in Combination With Intravenous Pembrolizumab in Patients With Advanced or Metastatic Solid Tumors

Key Inclusion Criteria: 1. Age 18 years or older. 2. Disease progression after standard of care (SOC) therapy or in the opinion of 3. The Investigator unlikely to benefit from SOC therapy. Inclusion Diagnosis Phase 1 - Histologically or pathologically confirmed locally recurrent or metastatic advanced malignancy. Phase 2a Part 1 i. Arm A - locally recurrent or metastatic melanoma. Participants must have received no more than 3 prior regimens for advanced or metastatic disease. ii. Arm B - locally recurrent or metastatic HNSCC. It must also meet the following criteria: 1) Disease progr…