The last time we saw Samwell Tarly on Game of Thrones, he was leaving home (again), only possibly for good this time. He brought Gilly and Little Sam home to for their protection, but after a family dinner from Hell, he took them and left again. So, where is Samwell Tarly now? His original destination was the Citadel so he could train to become a maester, since we all know he's more of a lover than a fighter. But women aren't allowed there, much less a woman he isn't even married to, carrying around a bastard child bred from the rape she endured from her own father. Yeah, it's all over the place.
Along the way, Sam decided to make a quick detour to his family's home at Horn Hill and while his mom and sister were pretty amazing to him, Gilly, and Little Sam, his father didn't even try to pretend to accept Sam or his companion who, he learned, was a Wildling. I guess people don't take too kindly to Wildlings when they have kind of a bad rap as a whole? Lord Randyll Tarly offered to keep Little Sam at Horn Hill, and give Gilly a job in the kitchen (really?), but Sam, being the sweetest of sweet men that he is, denied both of these.
So where did Samwell Tarly go from here? His only real destination was the Citadel, where he can gain the education he needs to work as a maester. Which is basically the same as an adviser, who will have the kind of knowledge and healing tools that everyone, from leaders to the Night's Watch, need. They've also been referred to, in the Game of Thrones universe, as "knights of the mind", which makes total sense, especially for Sam Tarly.
Sam and Gilly likely set out for the Citadel again, with no roadside stops along the way this time, and like most things with Sam, the whole no women allowed thing will be something he pushes past. This is the high-born first son of an important House of the Seven Kingdoms, who took Night's Watch vows and then denied them when he fell in love with the woman he saved. After taking a vow of chastity, mind you. Samwell Tarly doesn't care about your rules.
We haven't seen him much this season on Game of Thrones, but that's only because Samwell Tarly didn't have much of a place in the war of bastards and dragons that were playing out. But since Winter is coming (or has it arrived yet?) and we know things is about to hit the fan with those White Walkers, and my money is on Samwell Tarly playing a much larger role in Season 7 of Game of Thrones. He is one of the only people we've seen actually kill a White Walker on his own, and if he is going to study to be a maester, i.e. learn a ton of stuff, then we can assume that he's going to learn more about the White Walkers and the magic surrounding them.
Imagine a war in Season 7, between the thousands of White Walkers and much of the armies in both the North and South of Westeros. Suddenly, Sam Tarly rides up, spits out some knowledge or magic to help fend them off, and he's the hero we all knew him to be. Or, you know, something like that. The point is, Westeros is not yet done with Samwell Tarly, and while he studies to be a maester, he will be figuring out just how to be useful in their world.