Not only does Mass Effect 3 bring an epic conclusion of bioware's trilogy, it will also be the last time we will see Commander Shepard fighting to save the human race. Of course, we have no idea what happens to Shepard yet. Producer Michael Gamble says "After this, Commander Shepard's story is complete".
With that said, if there will be more games set in the Mass Effect universe , Shepard won't be part of it. This universe they created brings a lot of possibilities of a new focus. With the races, worlds, and other likable characters in Mass Effect, anything is possible after Mass Effect 3. It can be another RPG or a completely different game. This is definitely not the last time we see Mass Effect