The blue moon butterfly (hypolimnas bolina) has a recorded case of evolving to develop immunity to a parasite that was killing off the males. It developed genes to hold off the parasite and the male population recovered in less than one year.
Maybe one day humans will use genomics to develop immunity to any pandemic threat.
In the meantime we can admire the male blue moon butterfly. Its upperside is jet black with white spots surrounded by purple iridescence; its underside is brown. Two color schemes in one set of wings.