The goal of this observational study is to explore whether changes in peripheral blood effector tumor antigen-specific T cells (ETASTs) can predict treatment outcomes in patients with advanced non-small cell lung cancer (NSCLC) receiving chemoimmunotherapy. The study aims to:
* Evaluate the relationship between ΔETAST levels (baseline to cycle 2) and progression-free survival
* Compare the predictive performance of ΔETASTs with traditional biomarkers (PD-L1, TMB)
* Assess whether ΔETASTs can identify patients more likely to benefit from PD-1 inhibitor plus chemotherapy
Participants will:
* Provide peripheral blood samples at baseline and after cycle 2 of treatment
* Undergo ETAST quantification using the CTT-NanoDT technology with TATAN nanoparticles
* Have standard tumor assessments every 2 cycles according to RECIST 1.1 criteria
* Be followed for progression-free survival and overall survival up to 24 months