Of course, there is no way to know for sure what social trends will occur. However, we can speculate.
One social trend that seems to be coming is a greater movement towards allowing citizens to carry concealed weapons. This is likely to complicate policing to some degree. Police are going to have to be much more careful now since it may well be the case that they will be called to crime scenes where some people who have guns are the criminals and some are regular citizens. Police will have to deal with the extra confusion that this is likely to cause.
Another social trend that is already occurring but which is likely to accelerate is the increasing proportion of non-white people in the United States. This will pose some degree of challenge to the police because the police have not always had good relations with minority communities. There will be a need for more police officers from minority groups and for programs to help the police and minorities improve their relations with one another.
There are sure to be other social trends that impact policing in the next decade, but these are two of the trends that are more predictable at this point.