Jeff Sessions has said he will not endorse anyone in the primaries and in my opinion, he’s come as close as he possibly can right now with Trump. My guess is he will make the VP list to Trump to pick from if we get that far...
Sessions has also come as closely as he can to endorsing Cruz. But he’s a man of his word and won’t endorse. Joint appearances don’t mean a lot. Grassley’s appearance last week introducing Trump was writ large by Trump fans. But IIRC he’s scheduled to do the same for Cruz tomorrow. And IIRC Grassley was about the only one of the older GOP senators to speak during Ted’s fillibuster, so he doesn’t consider Ted ‘nasty.’