In our current paper, we will extract new unexpected diverse variety of the exact solutions to the Keller-Segel -Fisher system (KSFS) which is a famous mathematical biological model that governs the mechanism of bacteria to discovery food and gets rid of venoms. The suggested model plays a vital rule for health of humans, animals as well as all other organisms. There are three famous different techniques are introduced for extract and document these new unexpected behaviors of the exact solutions are the (G′ G ) -expansion method, the extended simple equation method (ESEM) and the Riccati-Bernoulli Sub-ODE method (RBSODM). We will implement these three proposed techniques in the same time and in arranged sequence. Furthermore, we will document and list a comparison between our new achieved exact solutions of this model each with each other as well as the previously documented solutions by other authors who studied this model before.