lead up to

phrasal verb

led up to; leading up to; leads up to

1

: to occur in the time that comes before (something)

Many voters were still undecided in the days leading up to the election.

2

: to come before and help to cause (something)

There was a series of errors leading up to the accident.

3

: to come before and help to introduce (something)

a chapter leading up to the main topic of the book

I had no idea what he was leading up to when he started talking about his father.