Annihilation by Jeff VanderMeer

Nature has reclaimed the last vestiges of human civilization. Expeditions into the zone have ended in disaster or death.

In Annihilation, we join the latest expedition group. Made up of four women: an anthropologist; a surveyor; a psychologist, the de facto leader; and the narrator, a biologist; their mission is to map the terrain, record all observations of their surroundings and of one another, and, above all, avoid being contaminated. They arrive expecting the unexpected, and the zone delivers--they discover lifeforms that surpass understanding. But it's the secrets they carried across the border with them that change everything.