Cells contain many receptors integrated into their membranes. They also communicate to other cells through secretion of signalling molecules.
It is very important for cells to be able to communicate with each other to maintain a single cohesive organism. If our cells didn't work together and communicate we would be a mass of cells rather than an organism of cells working together to serve a common purpose.
hope this helped :) if you have any other questions I'd be happy to answer them for you