[drocer88]

Yes ( well, maybe not "all" ). For example, Yescarta® is an FDA approved CAR T-cell therapy for patients with refractory b-cell lymphoma. From https://www.gilead.com/-/media/files/pdfs/medicines/other/ye... : "Before you get YESCARTA, you will get 3 days of chemotherapy to prepare your body". This chemotherapay is "lymphodepleting" ( https://www.yescartahcp.com/large-b-cell-lymphoma ). This chemotherapy decreases the number of T cells.

Gilead just reported a 5 year follow up on their therapy : https://www.gilead.com/news-and-press/press-room/press-relea... . " 92% of Patients Alive at Five Years Have Needed No Additional Cancer Treatments; Data Suggestive of a Potential Cure for These Patients "