Principles of Systemic Therapy for Unresectable Locally Advanced, Recurrent or Metastatic Disease...First-line Therapy...Preferred Regimens...HER2 overexpression negative...Fluoropyrimidine (fluorouracil or capecitabine), oxaliplatin, and nivolumab for squamous cell carcinoma...Fluoropyrimidine (fluorouracil or capecitabine), cisplatin, and nivolumab for squamous cell carcinoma