This is an important question and one that gets asked a lot, especially by new players or those going through a rough patch.
Personally, I believe cheating exists in any field where money is involved, and poker is no exception. Whether it's through external software or collusion between players, there have definitely been some real cases. But that doesn’t mean every loss is due to cheating. Most of the time, it's just natural variance or decision-making mistakes.
As for the idea of cheating— even if I had the tools and knowledge, I'm totally against it. For me, poker is a game of strategy and intelligence, and any win achieved through cheating is meaningless. The real joy comes from outplaying your opponents with smart decisions, not manipulation.
That said, it's still important to play on trusted platforms and take account security seriously.