What news does Michael Cassio bring when he enters?
In Act I, Scene 2, of Othello, Michael Cassio, Othello's recently promoted lieutenant, enters with officers from the Venetian court who bear torches. He has come to summon Othello, informing him, "It is a business of some heat" (1.2.40). This meeting is so important that the Venetian Senate has sent out three separate search parties to look for Othello. The Duke desires to speak with him because of trouble in Cyprus, an island which is controlled by Venice.
After Othello exits, Cassio asks what Iago is doing in the Duke's house. Iago suggests that Othello has "boarded a land carrack" (a merchant ship) and found a treasure. Cassio does not understand, so Iago tells Cassio that Othello is now married. But he does not mention that the bride is the Duke's treasured daughter.
A Florentine, Michael Cassio is the object of Iago's hatred and envy because Iago feels that Cassio did not deserve to have been chosen Othello's lieutenant instead of himself. Iago has the battle experience, not Cassio. But Othello has chosen Cassio because he is a theorist and a tactician.
Cassio comes to find Othello to tell him that the Duke and the Venetian senate needs to speak with him. He says that the Duke has received several messages from Cyprus (presumably about the invading Turks). This becomes important to the play because of the situation with Desdemona and Brabantio. Brabantio complains to the senate that Othello has stolen his daughter, but whereas they might have cared under other circumstances, they are more concerned about Othello defending Cyprus than about Othello's elopement.