Upon targeting these CSCs, the tumors were significantly responsive to chemotherapy, and cervical lymph node metastasis was obliterated.150 Moreover, there is growing evidence that these stem cells may manipulate the host immune response in cancer, promoting an immunosuppressive TME.146,151 We have further investigated BMI1+ CSC responses following a combination of cisplatin and PD-1 immunotherapy. Here, PDCD1 is linked to cancer.