Inclusion Criteria:
* Patients voluntarily participate in this study and sign informed consent;
* Patients aged ≥18 years and ≤75 years;
* ECOG score ≤2 points; Expected survival ≥6 months;
* Pathological diagnosis of advanced pheochromocytoma/paraganglioma: including clinical stage IV unresectable pheochromocytoma/paraganglioma with postoperative recurrence or metastasis;
* Unwilling or unsuitable for chemotherapy and radionuclide therapy.
* At least one measurable lesion (RECIST 1.1);
* The main organs function well, and the laboratory examination indicators meet:
1. Blood routine examination:
Hemoglobin (HB) ≥ 90g/L(5.6 mmol/L); Absolute neutrophil count (ANC) ≥1.5×109/L; Total white blood cells ≥3.5×109/L;
③ Platelet (PLT) ≥ 80×109/L;
Blood biochemical examination:
① Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 × ULN (liver metastasis/bone metastasis ≤5 × ULN; Bone metastases ≤5 ULN);
② Serum total bilirubin (TBIL) ≤1.5 × ULN;
③ Serum creatinine Cr≤1.5×ULN or creatinine clearance ≥60 ml/min; Blood urea nitrogen (BUN)≤2.5 × upper limit of normal value (ULN);
④ Albumin (ALB)≥30 g/L;
2. Blood clotting test:
* Activated partial thromboplastin time (APTT), International standardized ratio (INR), prothrombin time (PT) ≤ 1.5×ULN;
* Women of reproductive age must confirm their non-pregnant status before enrollment, and all enrolled subjects (whether male or female) should take adequate contraceptive measures during the entire treatment period and within 4 weeks after the end of treatment;
* The subjects voluntarily joined the study and were willing to return to the hospital for follow-up, and the compliance was good; Myocardial enzymes and ejection fraction were normal.
Exclusion Criteria:
* known allergic reactions to anrotinib hydrochloride capsules, Benmelstobart active ingredients or any excipients;
* Receiving anti-tumor monoclonal antibodies or other investigational drugs before enrollment; Previous treatment with other anti-PD-1 monoclonal antibodies or other medications targeting PD-1 / PD-L1;
* previous use of anrotinib hydrochloride capsules or other anti-angiogenic drugs, such as Sunitinib, bevacizumab, etc.;
* Patients were taking immunosuppressants or systemic hormone therapy for immunosuppressive purposes (doses greater than 10mg/day prednisone or other equivalent hormones) and were still taking them within 2 weeks prior to enrollment;
* The patient has any active autoimmune disease or a history of autoimmune disease; Have clinical symptoms or diseases of the heart that are not well controlled;
* Congenital or acquired immune deficiency;
* History of gastrointestinal perforation or open biopsy within 4 weeks prior to enrollment; ≥CTCAE grade 3 for any bleeding event, presence of unhealed wounds, ulcers, or fractures;
* Hyperarterial/venous thrombosis events occurred within 6 months before the study period, such as non-cardiovascular and cerebrovascular events (including temporary ischemic attack), deep vein thrombosis (except venous thrombosis caused by intravenous catheterization during previous chemotherapy and cured by investigators), pulmonary embolism, etc.; Cardiac angioplasty or coronary bypass surgery for unstable arrhythmia, unstable angina pectoris or myocardial infarction;
* People with active bleeding or bleeding tendency;
* Correcting QT interval \> 480msec; If a patient has QT interval prolongation, but the cause of the prolongation is assessed by the investigator as a pacemaker (and no other cardiac abnormalities), the patient should be considered suitable for inclusion in the study after discussion with the sponsor study physician;
* Patients suspected of having other primary cancers; Patients with other primary malignancies within the 5 years prior to the study (other than adequately treated cervical or skin cancer in situ, such as basal cell carcinoma, squamous cell carcinoma, or non-melanoma skin cancer);
* Combined diseases/medical history:
1. Clinically significant hemoptysis (\> 50ml daily hemoptysis) occurred within 3 months prior to enrollment; Or clinically significant bleeding symptoms or definite bleeding tendencies, such as gastrointestinal bleeding, hemorrhagic gastric ulcer, stool occult blood or above at baseline, or vasculitis;
2. hypertension, which is not well controlled by antihypertensive drugs (systolic blood pressure ≥150 mmHg or diastolic blood pressure ≥100mmHg); In the 6 months prior to randomization, the following conditions had occurred: myocardial infarction, severe/unstable angina pectoris, NYHA grade 2 or higher cardiac dysfunction, clinically significant supracentricular or ventricular arrhythmias, and symptomatic congestive heart failure;
3. interstitial lung disease, non-infectious pneumonia or uncontrollable systemic diseases (such as poorly controlled diabetes (fasting blood glucose (FBG) \> 10mmol/ L), pulmonary fibrosis and acute pneumonia, etc.); Renal failure requires hemodialysis or peritoneal dialysis; Liver cirrhosis, decompensated liver disease, active hepatitis (hepatitis B, defined as HBV-DNA ≥ 500 IU/ml; Hepatitis C, defined as HCV-RNA above the lower detection limit of analytical methods) or chronic hepatitis requiring antiviral therapy;
(6) Live attenuated vaccine vaccination history within 28 days prior to the first study or live attenuated vaccine vaccination expected during the study period; (7) Human immunodeficiency virus (HIV) infection or known acquired immunodeficiency syndrome (AIDS); Combined with hepatitis B and hepatitis C co-infection; Severe infection, including but not limited to bacteremia requiring hospitalization, severe pneumonia, etc. within 4 weeks before the first dose; Active infection of CTCAE grade ≥2 requiring systemic antibiotic treatment within 2 weeks prior to first administration, or unexplained fever \>38.5°C during screening/prior to first administration (fever due to tumor, as determined by the investigator, was eligible for inclusion); Evidence of active tuberculosis infection within 1 year prior to administration; Major surgery within 28 days prior to randomization (tissue biopsy required for diagnosis and insertion of a central venous catheter through peripheral venipentesis \[PICC\] or infusion PORT is permitted);
* Participants who have previously received or are preparing to receive allogeneic bone marrow transplantation or solid organ transplantation;
* Peripheral neuropathy ≥ grade 2; Patients with active brain metastases, malignant meningitis, spinal cord compression, or imaging CT or MRI findings of brain or pia disease during screening (patients with brain metastases who have completed treatment 14 days before enrollment and whose symptoms are stable can be enrolled, but only after brain MRI, CT or venography evaluation to confirm no symptoms of cerebral hemorrhage);
* significant factors affecting oral drug absorption, such as inability to swallow, chronic diarrhea, and presence of clinically significant intestinal obstruction.
* Women who are pregnant, breastfeeding, planning to become pregnant during the study period, or men or women who are fertile but do not want to use appropriate contraceptive methods.
* The presence of other serious physical or mental illnesses or abnormalities in laboratory tests that may increase the risk of participating in the study or interfere with the study results, and patients who are deemed by the investigato
* not suitable for participation in the study;
* Patients with brain metastasis;
* Imaging shows that the tumor has invaded important blood vessels, or follow-up shows that the tumor is highly likely to invade important blood vessels and cause fatal bleeding;
* Drugs that interact with anlotinib hydrochloride capsules/piamplizumab are being used;
