Colorectal cancer (CRC) is a major health concern and understanding its molecular characteristics is crucial for improving its diagnosis and treatment. Here, we present a comprehensive analysis utilizing RNA-sequencing (RNA-seq) data and clinical information from Korean patients with CRC. Differential gene expression analysis identified significant changes in gene expression between tumor and normal tissues. Gene Set Enrichment Analysis (GSEA) revealed dysregulated pathways associated with tumor progression. Furthermore, using CMScaller, we successfully stratified CRC tissues into distinct molecular subtypes. Upon reviewing the public consensus molecular subtype (CMS) signature, it was confirmed that it shares similar biological characteristics with the existing CRC. Additionally, biological characteristics of the group that could not be classified using CMScaller were found to resemble those of CMS2. Finally, distinguishing characteristics were observed between the tumor and normal groups when analyzed from an immunological perspective. Patients with CRC were checked for immunotherapy responsiveness, and those who clinically responded to immunotherapy were identified. Survival analysis confirmed that certain microsatellite stable (MSS) samples were responsive to immunotherapy and showed a relatively better prognosis. Furthermore, analysis of various immune cell types to identify genes involved in the response to immunotherapy revealed that RORC, NOS2, and KLRK1 are potential candidate genes. Our findings provide valuable insights into the molecular landscape of CRC in the Korean population and underscore the potential for integrating RNA-seq data with clinical information to improve cancer research and patient care. Immunotherapy was found to be effective in Korean patients with CRC.