Inclusion Criteria:  Subjects volunteered to participate in this study and signed the informed consent, with good compliance and follow-up; Male or female patients aged between 18 and 75 years; Patients with extensive small-cell lung cancer diagnosed by pathology, who have received only first-line chemotherapy and failed treatment, and who have measurable target lesions; Definition of treatment failure: disease progression or intolerance during or after chemotherapy treatment for who have previously received concurrent chemoradiotherapy or adjuvant chemotherapy, if recurrence/metastasis occurs within 6 months after the end of the last treatment, the original treatment plan is defined as the subject's first-line treatment plan. The interval between the time of disease progression and the end of the last systemic chemotherapy was less than 6 months; Life expectancy of at least 3 months, ECOG score: 0-1; The main organs are functioning normally  Exclusion criteria:  Patients with previous use of anlotinib capsules or other antiangiogenic drugs; Previous use of tislelizumab injection other anti-PD-1, anti-PD-L1, or anti-CTLA-4 antibodies, as well as any other antibody or drug therapy targeting T cell co-stimulatory or checkpoint pathways, such as ICOs or agonists (such as CD40, CD137, GITR, Ox40, etc.); Patients who have previously used Irinotecan injection or other camptothecin drugs Patients who have received two or more platinum-containing two-drug chemotherapy (adjuvant chemotherapy relapse time within 6 months is counted as first-line chemotherapy); Imaging (CT or MRI) showed obvious pulmonary cavitary tumor; History and complications