In Act 2 Scene 3 of Othello, Iago has been working tirelessly to carry out his evil plans. He has been planting seeds of doubt and suspicion in Othello's mind regarding Cassio and Desdemona's relationship. Iago has been acting as if he is Cassio's friend, while at the same time spreading lies about Cassio and Desdemona's supposed affair. He has been playing on Othello's insecurities and jealousy, making Othello believe that Desdemona is unfaithful. This has led Othello to become increasingly agitated and angry, setting the stage for the events to come.
Furthermore, Iago has been carefully manipulating Cassio as well. He has been encouraging Cassio to talk to Desdemona about interceding on his behalf with Othello, which will further fuel Othello's jealousy. Iago has been working to destroy the relationship between Cassio and Othello, and to turn Othello against both Cassio and Desdemona.
This latest development in Iago's plans marks a major turning point in the play as Othello's trust in Iago and his jealousy towards Cassio and Desdemona continue to grow. Iago is one step closer to realizing his ultimate goal of destroying Othello and gaining power and control.