In a clinical trial aimed to assess the efficacy and safety of combination treatment with lenalidomide and cetuximab in KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog)-mutant metastatic colorectal cancer patients, we assessed 25 different subpopulations of CD45+ immune cells (T cells, B cells, and NK cells). This evidence concerns the gene KRAS and metastatic colorectal cancer.