For example, Namor, the main antagonist of the film, threatens Wakanda with war to prevent them from exposing his civilization to the rest of the world. While Namor is not really recognized as having any legal power over Wakanda, this still prevents the Wakandans from openly discussing their situation and puts a lot of pressure on them, especially when they are also being threatened with political action from the rest of the world for hoarding their vibranium resources. 

Additionally, Everett Ross, a former CIA agent, faces a similar dilemma in the movie. Multiple times throughout the film he is in contact with the Wakandans and is constantly attempts to deescalate the situation between Wakanda and the rest of the world. Of course, he is legally not allowed to disclose the location of Riri Williams, the scientist that Namor is looking for, to the Wakandans due to federal restrictions, which is one of the ways his freedom of speech is violated. On the flipside, he is also unable to explain the full situation of the Wakandans to the CIA since the Wakandans request that he does not do so, and he feels indebted to the Wakandans for saving his life in the previous movie. 

While not actually censored in terms of speech, Riri Williams, the MIT student who develops the vibranium detector, gets her technology stolen from her by the government which can be considered a form of censorship. She is also forced to go into hiding, since she is being hunted both by the Talokans and the US Government, so this could be seen as a restriction on her freedom of speech as she is unable to disclose her location. Lastly, Williams imposes self-censorship, as she secretly has been working on an Iron Heart suit while she was in college and chose not to reveal that information to anyone.