CD274 and head and neck cancer: Finally, a phase II clinical trial (NCT04847466, Table 1) is evaluating the effectiveness of irradiated allogeneic PD-L1 CAR-NK cells in combination with pembrolizumab (PD-1 inhibitor) and N-803 (IL-15-based immunostimulatory fusion protein complex (IL15RaFc)), in patients with recurrent or metastatic gastric or head and neck cancer.