Can you use CBD Oil when taking Immunotherapy drugs?

My wife has small cell lung cancer, she has just had her first session of Chemotherapy and immunology( combined) and we would like to know how soon after the administration of the drugs we can start back on CBD Oil. She was taking it up till a day before the immunotherapy and has been advised by her immunotherapist that, as there are no conclusive studies that he has seen on the effects of CBD Oil on the immunotherapy drugs in the liver ) that he is of the mind not to take any (CBD) at this time. We were hoping someone has actually taken the CBD soon after, or even during, and had some good results and no adverse effects on the function of the drugs or the liver. cheers, iain salmond.