eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2026-03-20 19 1 79 98 10.13005/bpj/3339 70033 article Faruk Alam 1 Alindam Ghosh 1 Arpan Sen 2 Debraj Dey 2 Soumya Sunder Ghora 2 Saurav Guchhait 2 Department of Pharmaceutical Science, Assam down Town University, Guwahati, India. Department of Pharmaceutical Science, DmbH Institute of Medical Science, Hooghly, West Bengal, India. Department of Pharmaceutical Science, Royal School of Pharmacy, The Assam Royal Global University, Guwahati- Assam, India The immune system is a simple network of natural biological systems that protects an organism from diseases. It can discriminate between the organism's healthy tissues and unhealthy ones, such as various pathogens, including viruses, parasitic worms, cancer cells, and things like wood splinters. Living thing has an immune system in the form of enzymes. Ancient plants and animals developed additional fundamental immune systems, which are still present in their contemporary offspring. The complement system, phagocytosis, and antimicrobial peptides, such as defensins, are small cysteine-rich cationic proteins found in all cellular life, including plants, fungi, vertebrates, and invertebrates. Immunotherapy is a type of treatment that uses substances to stimulate or suppress the immune system to help fight diseases, such as cancer, Autoimmune diseases, Allergies, and the rejection of transplanted organs. Immunotherapy has been applied for years to treat allergies and prevent the body from rejecting transplanted organs. Immunotherapy is a class of treatments that harnesses a person's immune system to help kill cancer cells. The Immune system's function and immune therapy for treating liver cancer and collateral cancers are covered in this article. It draws attention to growths in targeted medicines, checkpoint inhibitors, and CAR T-cell therapy, emphasizing how these may strengthen immune responses and boost patient outcomes. For these cutting-edge cancer therapies to be optimized, ongoing clinical studies are essential. https://biomedpharmajournal.org/vol19no1/a-comprehensive-review-on-the-immune-system-and-immune-therapy-in-liver-cancer-and-colorectal-cancer/ Collateral cancer Hepatocellular carcinoma Immune system Immunotherapy Liver cancer