Treating cancer will always be an “arms race” against the cancerous cells. Whatever therapy is used it is never 100% effective and those cancer cells that survive are resistant to the latest drug. Also, the cost of autologous (patient donor) T cell therapies is in the millions making it too expensive for most insurance plans today. Allogeneic (stranger donor) therapies that use gene editing to knock out the graph vs. host disease (GVHD) gene and make it possible to create unlimited quantities of universal donor T cells would bring down the costs and time delay in treating cancers but are still years away.
Cancer cells also have evolved to turn off the ability of T cells to mark them for destruction using check point proteins. Recent advances like check point inhibitors have defeated this trick but this can also cause T cells to attack healthy cells leading to autoimmune responses which can be fatal.
Looking for a single silver bullet to defeat an evolving enemy like cancer is probably not going to work without addressing its complex lifecycle.
Might be interesting to see if any standardization in the process / equipment might bring down the cost. Graft vs. Host Disease.
See also Hunter Biden.