Anlotinib and Benmelstobart in DTC

Inclusion Criteria: * The patient voluntarily agrees to participate in this study and has signed the informed consent form; * Age: ≥18 years, regardless of gender; * Histologically confirmed differentiated thyroid cancer; * Unresectable or borderline unresectable locally advanced thyroid cancer and/or metastatic thyroid adenocarcinoma; * Failure of first-line treatment (failure to achieve partial or complete response) or disease progression after first-line treatment; * At least one measurable lesion; * ECOG PS: 0-2; * Expected survival period ≥12 weeks; * Patient agrees to undergo tumor tissue biopsy/surgery at the time of enrollment; * Normal function of major organs; * Willingness to use reliable contraceptive methods during the trial. Women of childbearing potential must have a negative pregnancy test (serum or urine) within 14 days prior to enrollment. * The subject voluntarily agrees to participate in this study, signs the informed consent form, demonstrates good compliance, and cooperates with follow-up. Exclusion Criteria: * Presence of other active malignancies within the past 5 years or concurrently. Patients with cured localized tumors, such as basal cell carcinoma of the skin, squamous cell carcinoma of the skin, superficial bladder cancer, carcinoma in situ of the prostate, carcinoma in situ of the cervix, carcinoma in situ of the breast, etc., may be enrolled. * Use of other antitumor therapies (including but not limited to chemotherapy, radiotherapy, etc.) w…