RecruitingPhase 2Biological interventionPD-L1 t-haNK, NAI IL-15sa and Cetuximab for Recurrent, Metastatic HNSCCThe purpose of this research study is to test the safety and efficacy of the combination of PD-L1 t-haNK (modified immune cells), NAI (a manufactured protein that stimulates the immune system), and cetuximab (a targeted antibody) in treating advanced head and neck cancer. The names of the therapies involved in this study are: * PD-L1 t-haNK cell therapy (a NK cell therapy infusion) * NAI (a type of recombinant human superagonist) * Cetuximab (a type of antibody)