I am about to write a story, but it seems like the premise is already taken. Can I still use it?

My premise is that it is illegal to die. That's right. In this world, death is illegal. <br><br>I think I may be late to the party here, but I've never heard of this concept before. In this world, people live forever. And it is illegal to die.<br><br>My question is, if death is illegal, can a person die of old age? Can a person die in a war? <br><br>This is the core of my story, which I am going to write. I want to explore this concept, and see how it works. But I am a new writer, and I was hoping I could get some advice from you guys. I have so many questions.<br><br>Can someone die from a natural cause? I'm talking old age, cancer, etc. <br><br>Can someone die from an accident?<br><br>Can someone die in a war?<br><br>If someone has been murdered, are the murderer and victim both charged with murder?<br><br>If someone dies by their own hand, is that murder as well?<br><br>If someone has a terminal illness, can they just die?<br><br>If someone dies by drowning, is that drowning or murder? <br><br>If someone is murdered, can their family sue? And if so, who would they sue? <br><br>What about old age? <br><br>I know this is a lot, and I'm sorry. But this is a whole new concept to me. <br><br>Thanks!