• Aged 18 years or older, of any gender.

• Histologically or cytologically confirmed advanced, metastatic, or recurrent solid tumors, including non-small cell lung cancer and breast cancer.

• Disease progression or intolerance after at least second-line standard therapy, including but not limited to surgery, chemotherapy, radiotherapy, targeted therapy, or immunotherapy.

• CEA positivity confirmed by immunohistochemistry (IHC) in tumor samples within 3 months of screening (clear membrane staining, with positivity rate ≥10%). If the IHC result is more than 3 months old, serum CEA must be above 10 ng/mL.

• At least one evaluable lesion according to RECIST 1.1, with a longest diameter of ≥10 mm for non-lymph node lesions and a shortest diameter of ≥15 mm for lymph node lesions. Malignant pleural effusion is acceptable for the chest infusion subgroup.

• For patients with malignant pleural effusion, accurate volume assessment of pleural effusion by imaging (CT or MRI) and cytological or thoracoscopic biopsy confirmation of malignant pleural effusion.

• ECOG performance status of 0-2.

• Life expectancy of 12 weeks or more.

• No serious psychiatric disorders.

⁃ The following organ function criteria should be met unless otherwise specified:

∙ Hematology: White blood cell count \>2.0×10\^9/L, neutrophils \>1.0×10\^9/L, lymphocytes \>0.5×10\^9/L, platelets \>50×10\^9/L, hemoglobin \>80 g/L.

‣ Cardiac function: Echocardiography showing ejection fraction ≥50%, with no significant abnormalities on ECG.

‣ Renal function: Serum creatinine ≤2.0×ULN.

‣ Liver function: ALT and AST ≤3.0×ULN (≤5.0×ULN for those with liver tumor infiltration).

‣ Total bilirubin ≤2.0×ULN.

‣ Oxygen saturation \>92% without supplemental oxygen.

⁃ Eligible for single or venous blood collection with no contraindications to cell collection.

⁃ Consent to use a reliable and effective method of contraception for 1 year after CAR-T cell infusion (excluding the rhythm method).

⁃ The participant or their authorized guardian agrees to participate in the clinical trial and signs the informed consent form (ICF), indicating an understanding of the trial's purpose and procedures.