Please pay attention. I did not say "cancer or whatever". I said cancer [0], a specific family of diseases characterized by normal cells becoming cancerous [1], a state marked by unbounded growth and self-reinforcing DNA damage. Cancer and aging are intimately linked via telomeres [2], part of the structure of cellular DNA. Indeed, quoting the first sentence of [3]:

> Telomeres, the caps on the ends of eukaryotic chromosomes, play critical roles in cellular aging and cancer.

On war, we lose millions of people regularly [4]. We lose about a million people to genocide every year [5]. These are people that, in Bostrom's parlance, we have put on the train to go see the dragon; we sacrificed them for nothing at all. Nothing in Bostrom's tale suggests that, having defeated the dragon, we will stop killing millions of people.

On nuclear war or other disastrous climate change, something you only allude to, the Doomsday Clock [6] is currently at less than two minutes to midnight, and has never been closer. It is widely agreed that we are on the very edge of self-annihilation and that we expend a tremendous amount of political effort simply not destroying ourselves.

I can see that you're a relatively young and inexperienced account; I hope that you do some reading and improve your understanding of biology and history, rather than continuing to lean on mystic or mythic influences for your worldview.

[0] https://en.wikipedia.org/wiki/Cancer

[1] https://en.wikipedia.org/wiki/Carcinogenesis

[2] https://en.wikipedia.org/wiki/Telomere

[3] https://en.wikipedia.org/wiki/Telomeres_in_the_cell_cycle

[4] https://en.wikipedia.org/wiki/List_of_wars_by_death_toll

[5] https://en.wikipedia.org/wiki/Genocide

[6] https://en.wikipedia.org/wiki/Doomsday_Clock