CTLA4 and head and neck squamous cell carcinoma: For instance, the phase II study by Ma et al. investigating neoadjuvant tdRT combined with anti-PD-L1 and anti-CTLA-4 in HPV + HNSCC demonstrated impressive immune priming and tumor response; however, a 26% locoregional recurrence rate was observed at a median of 3 months following pathologic complete response9.