later on
Later; not now.
Finish your lessons. Later on, we may have a surprise.
Bill couldn't stand on his head when school started, but later on he learned how.
sooner or later
At some unknown time in the future; sometime; eventually, after a period of time.
John will come back sooner or later.
Grandpa is very slow about fixing things around the house, but he always does it sooner or later.
If you study English seriously, sooner or later you'll become fluent.
I'm too tired to do my homework now; I'm sure I'll do it sooner or later.