Is there a movie based on the book childhood's end by Arthur C Clark?

There hasn't been a movie based on the book. A movie of the same title was made but wasn't about Karellen or the Overlords but about teenage sexuality.

Several people have bought the rights to several of Dr Clarke's stories but nothing has been filmed that I am aware of since 2010, unless you count "Deep Impact" being loosely based on "The Hammer of God". Hope this helps.