I wonder then why Jeff Sessions is so strongly supporting Cruz on this issue, saying Cruz has been with him all the way, iirc. ?
I suggest you read closely what Sessions said in support of Cruz. Still, Cruz followed the Sessions lead and was against the bill. This was at a time when Ryan and Rubio were supporting it along with much of the GOPe. The Cantor defeat in the primary by Dave Brat sent a big time message that now was not the time for such a bill.
I was personally involved in helping to defeat the bill as part of a grassroots immigration organization that lobbies on the Hill. Despite some of the claims to the contrary, it was Jeff Sessions who led the fight in the Senate to kill the bill.