leave behind vs walk back

leave behind

verb
  • Used other than figuratively or idiomatically: see leave, behind. 

  • To pass. 

  • To abandon. 

  • To leave (a trace of something). 

  • To not live longer than; to be survived by. 

  • To forget about. 

  • To outdo; to progress faster than (someone or something else). 

walk back

verb
  • Used other than figuratively or idiomatically: see walk, back. 

  • To withdraw or backpedal on a statement or promise. 

How often have the words leave behind and walk back occurred in a corpus of books? (source: Google Ngram Viewer )