Not animals or plants, Us.
It really is not about saving any animal or plant. But saving them will save us. Biodiversity loss is by far the biggest extinction risk we face, as complex natural systems collapse, and fish, meat and oxygen supplies fail.
Talking about saving whales or rhinos does not connect us to the issue of the loss of our human lives which is enevitable if we continue taking resources and destroying Earth systems.
Talking about saving the planet are nonsense: the planet will be fine, some plants and animals will survive, but if temperatures rise to the forecast 3-4oc humanity will not. Before that, many will suffer with pre-extinction disasters such as heat death, drought, floods, malnutrition and related mass-migration and conflict.
As wild places are lost, wild animals and their diseases come into more frequent contact with domesticated animals and we see the spread of diseases such as COVID-19.
If we save the nature of which we are part, we save ourselves.