Inclusion Criteria for patients with locally advanced gland cancer at high-risk of recurrence must meet all entry criteria for participation in this study:  Locally advanced salivary gland carcinoma patients with high risk of recurrence confirmed by histology, the main pathological subtypes include:  Mucoepidermoid carcinoma Salivary duct carcinoma Non-specific adenocarcinoma Pleomorphic adenocarcinoma, etc. Expected survival ≥ 6 months Patients with prior standard surgery and post-operative radiotherapy (chemotherapy) Adequate function of main organs Sufficient tissue samples for gene mutation test Signed informed consent  Inclusion Criteria for patients of advanced gland cancer must meet all entry criteria for participation in this study:  Histologically confirmed recurrent or metastatic salivary gland cancer, the main pathological subtypes include:  Mucoepidermoid carcinoma Salivary duct carcinoma Non-specific adenocarcinoma Mastoid secretory carcinoma Pleomorphic adenocarcinoma, etc. a measurable lesion according to Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1) Expected survival ≥ 6 months Adequate function of main organs Sufficient tissue samples for gene mutation detection Signed informed consent.  Exclusion Criteria for patients with locally advanced disease at high-risk of recurrence who meet any of the exclusion criteria at baseline will be excluded from the study:  Severe or uncontrolled medical conditions (i.e., uncontrolled diabetes, chronic kidney disease, chronic lung disease or active uncontrolled infection, psychiatric illness/social situations that would, in the opinion of the investigator, confound the analysis of response to study treatment) Pregnancy or breastfeeding, or any patient with childbearing potential not using adequate pregnancy prevention  Exclusion Criteria for patients with advanced disease who meet any of the exclusion criteria at baseline will be excluded from the study:  Primary lesions amenable to local therapy Severe or uncontrolled medical conditions (i.e., uncontrolled diabetes, chronic kidney disease, chronic lung disease or active uncontrolled infection, psychiatric illness/social situations that would, in the opinion of the investigator, confound the analysis of response to study treatment). Pregnancy or breastfeeding, or any patient with childbearing potential not using adequate pregnancy prevention