Apple is just one of many companies that the US is investigating in light of possible antitrust violations. Most recently, the Department of Justice interviewed select Apple app developers about their place on the Apple App Store as part of their antitrust probe. For example, one app creator had their activity tracking app removed at some point while Apple was releasing its Screen Time function as part of their updated OS. Such an action was seen as Apple manipulating the market, to the point of making competition difficult between individuals.
The probe was announced in June 2019 after Trump had openly criticized several big tech companies earlier that year about possible censorship of conservatives (a claim that has little evidence). But Attorney General William Barr stated that he hoped the investigation would be finished by the end of 2019. It has not yet wrapped up.
While conservative politicians have vocalized their issues with Google and Facebook, it’s also expected that any Democratic candidate who wins the election will also push for stronger antitrust actions, including actions that could lead to the severance of bigger companies into smaller organizations, or penalizing companies that reach a certain size.