Inclusion Criteria:  Adult patients (age 18 or above), gender unlimited; Pathological diagnosis of non-small cell lung cancer stage IIIB or above; Agree to carry out the standard first-line chemotherapy combined with immunosuppression established in this study; Consent to 18F-FDG PET/CT imaging and related laboratory examination before and during treatment; The patients themselves or their legal representatives are aware of this study and can sign the informed consent.  Exclusion Criteria:  Acute systemic diseases and electrolyte disturbances; Pregnant or lactating women; The patient or his legal representative is unable or unwilling to sign the informed consent.