"Cold Heart (PS1 Remix)" by Elton John and Dua Lipa is a combination of two songs: Elton John's "Rocket Man" and "Sorry Seems to Be The Hardest Word." The lyrics are about a man who is struggling with his emotions and the consequences of his actions. He has a "cold, cold heart" that has been "hardened" by another person's actions. The scent of this person lingers, tempting him, but he knows that he needs to move on.

The chorus sung by Dua Lipa speaks of the man feeling like he is living a lie and not being the person that others believe him to be. He knows he should have been more honest about his feelings, and he regrets keeping them bottled up inside. He feels that it will take a long time before he is able to come to terms with his true self and be comfortable with who he is.

The overall theme of the song is the struggle to come to terms with one's emotions and identity. It encourages honesty and openness in order to avoid living with regrets.