Mutant RAS and the tumor microenvironment as dual therapeutic targets for advanced colorectal cancer

•RAS mutations occur in roughly half of the patients with colorectal cancer (CRC).•Oncogenic RAS induces a pro-metastatic immunosuppressive tumor microenvironment.•This suppressive environment prevents effective anti-tumor immune responses.•Effective treatments tailored to KRAS mutant metastatic CRC are needed.•Focus should be on combinations of immunotherapy with RAS-targeted treatments.