The highest wet bulb temperature that humans can survive is 35 degrees Celsius; above that the human body cannot dissipate the heat it makes and will die. In the tropics between 20 degrees north and 20 degrees south latitude, the wet bulb temperature can be only a few degrees below 35 C, and climate change may cause this to go even higher until it reaches 35 degrees Celsius or more. In this case, in some areas humans may not be able to live. I didn’t see anything about other warm-blooded animals but I assume they would not be able to survive, too.
In this YouTube video, Dave of Just Have Another Think explains.