The immune system's functionality is driven by its diversity at the cellular (immunophenotypic), transcriptional, and genetic (immunogenetic) levels. Significant progress has been made in understanding immune cell characteristics across these biological dimensions, both in normal conditions and during neoplastic transformation. However, critical gaps remain in fully integrating data from these modalities to achieve a detailed understanding of lymphocytes, particularly in their normal state and potential neoplastic progression. This thesis addresses these gaps by conducting a comprehensive analysis of lymphocytes from both normal and neoplastic conditions, leveraging multi-modal data integration. Additionally, it explores the application of advanced sequencing technologies to enhance the understanding of immune repertoire diversity by capturing full-length repertoire sequences, emphasizing the value of these integrative approaches in addressing fundamental biological questions related to immune system diversity.