Issac - personally, I don't adhere to any 'typical' keynote presentation. Unless the conference organisers specifically state an exact content and time etc - then the keynote is an open invitation to showcase that keynotes standing and expertise related to the conference themes. Tht can range from a personal and anecdotal account of ones life story and journey to date (usually the most interesting and humorous) - through to a specific account of recent/current research projects.
Dear Isaac Odun-Ayo in most international conferences keynote lectures are the highlights of the meeting. They are normally presented by established and excellent scientists who are well known for their achievements in their respective field of research. As pointed out by Dean Whitehead these lectures often comprise the life story of the researcher and are of broader interest than specialist talks. I would see keynote lectures as "spoken review articles". They are normally scheduled for 45 or even 60 minutes. For example, the title of a keynote lecture which I presented recently is "My 40-year organometallic journey through the Periodic Table with frequent stops at the rare-earth elements". Our work is summarized in the word cloud cited below.
Presentation Representation of our research 1980–2020
Isaac Odun-Ayo there are also a number of useful links and articles available in which the writing of a good keynote speech is addressed. For example, please see