The combination of Sintilimab (ICI) and Bevacizumab (anti-angiogenic) improved the tumor immune microenvironment (increased CD8+ T cells, decreased TAMs/CAFs) and clinical efficacy (ORR) in MSS/pMMR advanced CRC patients after 1st-line failure, with a manageable safety profile comparable to chemotherapy. The gene discussed is CD8A; the disease is colorectal carcinoma.