• Willing and able to participate in the study and provide written informed consent

• Be ≥ 18 years of age on the day of signing the Informed Consent Form

• Patients must have thyroid cancer that meets one of the following diagnoses, and, prior to lymphodepleting chemotherapy (LDC), have an identified available fresh or archival biopsy sample:

∙ Anaplastic Thyroid Cancer BRAF wild-type at any stage, including newly diagnosed

‣ Anaplastic Thyroid Cancer BRAF mutant after failure of or inability to tolerate BRAF- specific therapy

‣ Poorly Differentiated Thyroid Cancer that has failed any of the following treatments: surgery radioactive iodine, chemotherapy, radiation therapy, and/or targeted therapies

• Measurable disease by Computed Tomography (CT) or Positron Emission Tomography (PET) PET/CT per RECIST v1.1

• a. For ATC patients who do not have measurable disease at Screening, they are required to have measurable disease at Baseline Day -7 to proceed in the study.

• Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2

• Life expectancy greater than 8 weeks

• Overall adequate hepatic, renal, bone marrow, cardiac, and coagulation function, defined as the following:

∙ Estimated creatinine clearance ≥ 50 mL/minute

‣ Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST): normal or Grade 1. Note: Lymphodepleting Chemotherapy (LDC) agents can cause fluctuations in hepatic enzymes.

‣ Serum total bilirubin: normal or Grade 1. Note: LDC agents can cause fluctuations in hepatic enzymes.

‣ Serum albumin: normal or Grade 1. (human albumin supplementation is not allowed within 2 weeks prior to Screening assessment)

‣ Hemodynamically stable and left ventricular ejection fraction ≥ 45%

‣ Hematological parameters

• i. Absolute neutrophil count \> 1000/μL without myeloid growth factor support for ≥ 2 weeks

• ii. Absolute lymphocyte count ≥ 100/μL at screening and at apheresis

• iii. Platelet count ≥ 50 × 1000/μL without platelet transfusion for ≥ 2 weeks

• iv. Hemoglobin concentration \> 7 g/dL without red blood cell transfusion for ≥ 2 weeks

• Has met the minimum washout time for previous cancer treatments before undergoing apheresis or LDC, and in the Investigator's judgement, the patient is able to safely undergo the procedure

• (incorporated into inclusion criteria #7)

⁃ Females of reproductive potential (defined as all females physiologically capable of becoming pregnant) must agree to use 1 highly effective method of contraception and 1 additional effective method from at least 30 days before enrollment/apheresis and for at least 1 year after the infusion of AIC100 CAR T Cells.

⁃ Females of reproductive potential must have a negative serum beta-human chorionic gonadotropin pregnancy test result at Screening