While Google searches for the term "fake news" show a sudden spike in interest after October 2016, fake news is not new. That's why it is important to know the source, who or what is funding or sponsoring that source, and check biases before passing along what could be misinformation. For more on how to judge information, please see Evaluating Sources.
Similarly, deepfakes only emerged within mainstream consciousness in February 2018. To spot a deepfake: watch for glitches or irregularities around the mouth and sides of the face of the person depicted, take note of changes in lighting or shadows, and compare to pictures and videos confirmed to be the real person. For law review articles about deepfakes, see Scholarly Publications.
Finally, PSYOPs have been studied for awhile. Google searches for the term spiked in February 2005 and June 2020, although searches for the term continue to be popular. These spikes are likely due to U.S. military operations in Iraq (which held its first parliamentary election since the fall of Saddam Hussein's regime on February 1, 2005) and the COVID-19 pandemic, respectively. Whereas there were psychological operations in Iraq, COVID-19 is very real.
Fake news: “Fictions deliberately fabricated and presented as non-fiction with the intent to mislead recipients into treating fiction as fact or into doubting verifiable fact.” Eric Emanuelson, Jr., Fake Left, Fake Right: Promoting an Informed Public in the Era of Alternative Facts, 70 Admin. L. Rev. 209, 218-19 (2018).
Deepfakes: Media created with machine learning and/or artificial intelligence in which a person in an existing image or video is replaced with someone else’s likeness. Viorela Dan et al., Visual Mis- and Disinformation, Social Media, and Democracy, 98 Journalism & Mass Communication Quarterly 641, 643 (2021).
Misinformation: A “verifiably false statement of fact.” Charles R. Corbett, Chemtrails and Solar Geoengineers: Governing Online Conspiracy Theory Misinformation, 85 Mo. L. Rev. 633, 652 (2020).
Disinformation: "[F]alse information that is purposely spread to deceive people." David M. J. Lazer et al., The science of fake news, 359 Science 1094 (2018).
Information literacy: A set of "competencies that enable people to critically and effectively engage with communications content; the institutions that facilitate this content; and the use of digital technologies." Media and information literate citizens: think critically, click wisely!, UNESCO Digital Library.
Psychological Operation (PSYOP): "Often confused with Information Operations as a whole, PSYOP refers to influence activities specifically intended 'to induce or reinforce foreign attitudes and behavior in a manner favorable to U.S. objectives.'" 12 (March 8, 2011) Terrorist Use of the Internet: Information Operations in Cyberspace.