The study examined the effects of the drug on dMMR/MSI-H mCRC patients belonging to various subgroups, including those with positive (≥1%) or negative (<1%) tumor PD-L1 expression, tumors containing serine/threonine-protein kinase B-Raf (BRAF) or Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations, and patients with or without a clinical history of Lynch syndrome. The gene discussed is KRAS; the disease is Lynch syndrome.