FAS and neoplasm: As an important effector in innate immunity, NK cells exhibit a significant anti‐tumor effect and possess a broad range of applications in tumor immunotherapy.[1] There are several mechanisms by which NK cells induce apoptosis of stressed cancer cells:[1b] i) Several tumor necrosis factor (TNF) superfamily members such as Fas ligand (FasL) and TNF‐related apoptosis‐inducing ligand (TRAIL) expressed by NK cells induce apoptosis of target cells via binding to their corresponding receptors FAS or TRAILR, respectively.