Cancer cells express proteins that communicate with lymphocytes (white blood cells) to block apoptosis (cell death). We can't target the cancer cells, so we tw

Cancer cells express proteins that communicate with lymphocytes (white blood cells) to block apoptosis (cell death). We can't target the cancer cells, so we tweak the lymphocytes to block PD-1 receptors, thus ignoring ALL cells that express a lot of PD-L! protein. This unfortunately includes healthy cells.