Based on the high expression of PD-L1, an optimum strategy was used, combining immunotherapeutic agent, sintilimab, with an anti-angiogenesis drug, anlotinib. The patient obtained remarkable tumor shrinkage and an 18.3-month-sustained remission period. This is an effective case of using immunotherapy and anti- angiogenesis agent in the first-line treatment of ATC. It demonstrates a feasible and novel therapeutic option for future treatment of ATC patients.