Q: Can't shift gears

This is a common issue. There are several components that can fail to prevent the shifting out of park. The interlock system has two things that often fail, the switch itself and the electronic interlocking mechanism itself. If the switch fails, often times the cruise control or brake lights will stop working as well. The mechanism fails often times due to debris falling through the console into the shifter itself. Things like food, drinks, coins, etc can all cause an issue if they accumulate in the right area. The other issue that is common is cable failure. If the cable has a problem, it can keep the shifter from working properly. I suggest having a certified technician diagnose your gear shifting issue to determine what fixes should be made.