Is evolution still possible on a large scale?

[Kirker]

So i was thinking about how evolution works, and i realized that at this point there is a huge amount of humans on this planet. And evolution occurs by having one creature with a beneficial mutation that makes it easier for it to survive/find a mate. So if one human with a beneficial mutation is born, is there any possibility that the new type of mutated human could overtake the current population of average humans? and if not doesn't that mean that evolution ceases to happen in today's world?

Any clarification on this would be greatly appreciated.