The Maneuvering Characteristics Augmentation System (MCAS) is 
a flight control law managed by the flight control computer (FCC) and 
introduced on the 737 MAX to help it handle like a 737 Next Generation (NG), 
particularly at slow speeds and high angles of attack (AOA).
-From: https://aviationweek.com/commercial-aviation/boeing-737-max-mcas-explained 

MCAS is a longitudinal stability enhancement. 
It is not for stall prevention (although indirectly it helps) or to make the MAX handle like the NG (although it does); 
it was introduced to counteract the non-linear lift generated by the LEAP-1B engine nacelles at high AoA and 
give a steady increase in stick force as the stall is approached as required by regulation.
-From: http://www.b737.org.uk/mcas.htm