For one thing human evolution does not extend back 50 million years. Fever and chills are systemic responses. Fever is controlled by the hypothalamus when acted upon by the molecule PGE2. Bavi has its effects in the tumor microenvirnoment and tumor vasculature and does not seem to trigger such systemic responses when it is acting locally.
You guys better listen to FTM for he knows what he is talking about. It is specific signaling that Bavi is stopping and it is not causing a general immune reaction nor "fooling" the immune cells.
When you cut your finger and it gets infected do you get a fever? Usually not, it is only when the infection can't be controlled locally by the immune system and it spreads. Then prostaglandin E2 (PGE2) gets in your blood and travels to the hypothalamus in your brain which controls your body temperature.