CAR-T Immunotherapy is the newest treatment for some leukemias and for non-Hodgkin lymphoma. A good overview can be found on the National Cancer Institute website:
https://www.cancer.gov/about-cancer/treatment/research/car-t-cells
and on the Mayo Clinic page for CAR-T
https://www.mayoclinic.org/departments-centers/car-t-cell-therapy-program/home/orc-20404317
Copy and paste each in your browser to find out more.

My husband had this procedure in May-June 2018. It's very rough, but it worked for him. CAR-T is, as I understand, is not a first option treatment. Before his CAR-T, my husband had exhausted every other treatment option, including R-CHOP chemotherapy (in our city) and an autologous stem cell transplant (at Mayo). But his cancer, T-Cell Rich B-Cell non-Hodgkin Lymphoma, returned, and he was considered terminal in March 2017. But CAR-T passed clinical trials and was approved as a treatment by the FDA that autumn. After CAR-T, however, he is now in remission. Not all patients are eligible for CAR-T. Luckily, my husband's cancer advanced very slowly, and he was still asymptomatic and feeling find, with no other underlying health issues (diabetes, heart disease, etc.) when we went to Mayo's for the pre-tests. A patient must undergo a battery of pre-tests to ensure he or she can withstand the serious, but temporary, neurological and other side effects and the stress the treatment inflicts on the heart, kidneys, liver, etc. My husband had these serious side effects, but none was permanent. CAR-T treatment lasts about eight weeks, including, most often, one to two weeks of in-patient hospitalization when the side effects happen (usually very shortly after the T-cells are reinfused). If the patient is not hospitalized, he or she must go to outpatient clinic every day to be monitored over the course of the treatment. To undergo the CAR-T treatment, a patient must bring along a caregiver who is willing to assist in every way possible and observe the patent--24 hours a day. (Believe me, this was needed!) When the patient returns home, there is usually a week or two of recuperation before the patient feels like returning to work for a sendentary job (like my husband's). This recuperation would be longer if your had a job that required more physical or strenuous work. Also, the patient must return to Mayo's every three months or so for follow-up PETs and blood tests for a year and more. My husband was treated at Mayo's. I can't recommend Mayo's enough. The CAR-T team--everyone from doctors, physician assistants, nurses, physical and occupational therapists, well--everybody!!--was stellar. We will never forget the wonderful people we met. They are the very best!