Head and Neck Cancer (H&Amp;Amp;Amp;N)

This is a Phase I, open-label, dual-cohort clinical trial designed to evaluate the safety, tolerability, and preliminary efficacy of intratumoral injection of recombinant human endostatin adenovirus in combination with a PD-1 inhibitor in patients with recurrent or metastatic head and neck cancer, or in patients with esophageal squamous cell carcinoma (ESCC) with superficial lymph node metastasis.