Abstract

Predictive and prognostic biomarkers are vital for immune checkpoint blockade in solid tumors. Established markers include PD-L1 expression, \textit{Tumor Mutational Burden} (TMB), and Microsatellite Instability (MSI), guiding personalized treatment. Understanding mechanisms of response and resistance is key. Emerging biomarkers like tumor microenvironment features, gut mi crobiome characteristics, and specific gene signatures offer new insights. Non-invasive liquid biopsies, detecting circulating tumor DNA(ctDNA)andcells,providereal-timeinformation ontumorevolution andresponse. Proteomicanalysis further enhances predic tion by revealing complex biological pathways. These diverse biomarkers are crucial for optimizing patient selection and improving immunotherapy outcomes.