Immunotherapy helps our immune system to fight cancer by helping the immune cells recognise and attack cancer cells. There are several types of immunotherapy which have different mode of actions. You might need to have some tests to look for specific changes in proteins or genes in your cancer cells or blood sample to find out which (if any) type of treatment is likely to work. The decision and choice of immunotherapy as well how it is given (whether in combination with other treatment modalities) depends of the type and stage of cancer you have.