Uncharted 5, if it is real, will not follow Cassie Drake.

Uncharted 4 was released in 2016 and presumably takes place the same year. In the epilouge Cassie is 15, putting the ending of the game in the year 2031 at the earliest.

Ten years have passed since Uncharted 4 and assuming that this is a sequel and not a remake, that time has also passed in-universe. This means it would be in 2041.

2041 is a sci-fi year. I mean, it'll be here before we know it but also has the same vibe as Deus Ex: Human Revolution taking place in 2027 and releasing in 2011. Naughty Dog would have to make predictions about technology, social and political trends, etc. I don't see them taking the Uncharted franchise that direction.