Non-small cell lung cancer patients may have brain metastases at diagnosis. Patients with brain metastasis may contribute as poor prognosis factors. This trial aims to explore the efficacy and the safety of immune checkpoint inhibitors in non small cell lung cancer patients with initial brain metastasis.

Inclusion Criteria:

• 1.Diagnosed with advanced non-small cell lung cancer 2.Patients with brain metastasis 3. Treated with ICIs

Exclusion Criteria:

• 1.Patients with a clear driver mutation that can be targeted for first-line treatment

Patients with brain metastasis received immunotherapy