PDCD1 and head and neck squamous cell carcinoma: Another study aimed to reverse resistance to PD-1 inhibitors by using nanoparticle albumin-bound (nab) paclitaxel in combination with nivolumab as the treatment of recurrent or metastatic head and neck squamous-cell carcinoma (RM-HNSCC), which progressed on a PD-1 inhibitor [49].