There are many examples of Macbeth and Lady Macbeth overtly lying and cheating to gain power in Macbeth. While these characters demonstrate the most extreme deception in the play, there are other characters who put on false appearances to gain more power. I'll highlight some of these instances below:
Malcolm: One of the most interesting scenes in Macbeth is Act Four, Scene Three because Malcolm is potentially deceiving Macduff to test his loyalty. In the beginning of the scene, Malcolm plays that he has more vice than Macbeth. Macduff believes Malcolm and Macduff cries that the Scotland he knew is lost. However, Malcolm quickly shifts when he sees this display of emotion, claiming that Macduff's noble passion has changed him. In this instance, Malcolm puts on a different face to gain power and better understand Macduff's loyalties.
Banquo: At the top of Act Three, Banquo privately admits that he is suspicious of Macbeth. He is a loyal character, but he starts to be more reserved in Act Three. His soliloquy at the top of the act suggests that even Banquo will put on a false appearance in order to better understand a situation or truth.
During the battle in Act 1, Scene 2, we learn that the thane of Cawdor was one of the traitors who led the uprising against King Duncan. Later, after Cawdor is executed, Duncan reflects: "There's no art to find the mind's construction in the face. He was a gentleman on whom I built an absolute trust."
So, even before we meet Macbeth and Lady Macbeth, we are introduced to this recurring theme of characters showing one face to others while hiding their true intentions.
The witches are also constantly lying and cheating in their dealings with Macbeth, although it's never quite clear exactly what they have to gain from their mischief. In Act 1, scene 3, they speak to Macbeth and Banquo in contradictions, like "Lesser than Macbeth and greater" and "Not so happy, yet much happier." Later, their prediction that "none of woman born shall harm Macbeth" turns out to be a sneaky, misleading technicality when Macduff (who was "from his mother's womb untimely ripped") kills Macbeth.
The idea that there are liars everywhere is summed up by Macduff's son in Act 4, scene 2. When Lady Macduff tells the boy that traitors must be hanged by honest men, her son responds, "Then the liars and swearers are fools, for there are liars and swearers enough to beat the honest men and hang them up." In this play, even a child knows that the world is full of people lying and cheating to get ahead.