(be) hot on sb's `heels:following sb very closely 紧跟某人; 接踵而来.
I'm sorry,sir,there is no such a "hot off the heels" I can consult.you can check here:forum.wordreference.com/showthread.php?t=1666388
ps:there is another phrase named as:"hot off the press" 刚刚印出来的,刚刚发布的