Cancer immunotherapy has revolutionized the landscape of cancer treatment, offering promising outcomes for patients across various cancer types. However, the efficacy of immunotherapy remains variable among individuals, necessitating the identification of biomarkers and genetic signatures to predict treatment response and patient outcomes. This paper provides a comprehensive overview of the genetic basis underlying cancer immunotherapy response, focusing on the identification of biomarkers and genetic signatures that can inform treatment efficacy and patient prognosis in immunooncology. Understanding the genetic determinants of immune response to cancer is crucial for optimizing immunotherapy strategies. Biomarkers, both predictive and prognostic, play a pivotal role in guiding treatment decisions and stratifying patients based on their likelihood of responding to immunotherapy. Current biomarkers, such as PD-L1 expression and tumor mutational burden, have demonstrated utility in certain contexts but exhibit limitations in predicting treatment response across all patients. Thus, there is a pressing need to explore novel biomarkers that capture the complexity of the tumor-immune microenvironment. Genomic profiling techniques have enabled the identification of genetic signatures associated with immunotherapy response. By analyzing the tumor genome, transcriptome, and immune landscape, researchers have identified candidate genes and pathways implicated in modulating the response to immunotherapy.