What is the duration of a Global Talent visa?

After being granted a Global Talent visa, you can stay in the UK for up to 5 years at a time. There is no limit to how long you can stay in the UK in total, but you will need to extend your visa when it expires. Each extension can last from 1 to 5 years. 

You may be able to get indefinite leave to remain in the UK after 3 or 5 years, depending on the endorsement path you are applying for.