2018 MARKET UPDATE: NEVER AN AVENGERS MOVIE WITHOUT HER
I haven't seen it yet, but my best guess is that the Black Panther movie will be another Avengers movie, and so was the last Captain America movie.
Infinity War will DEFINITELY be an Avengers movie.
The lovely Black Widow was, or will be, in all of them. Prices of her first appearance are hot in low-to-mid grades, while upper grades are quiet.
2017 MARKET UPDATE:
To some degree, the excitement about this book is all in the past. Many key issues driven by movies have a spike and then drop again. TOS 52 has the advantage of multiple movies featuring Black Widow. She's one of the characters which crosses over into many of the stories.
Few high-grade examples have come to market recently. When they do, new records will probably be set. This is a tough book in higher grade, due to its dark cover.
There are few characters in the Marvel Cinematic Universe hotter than Black Widow (especially considering her on-screen persona is acted by the uber-hot Scarlett Johansson).
Tales of Suspense #52 is one of the most underrated and under-valued Silver Age keys, in our opinion, and it is beginning to catch fire, as more investors and speculators jump into nice-looking copies of this book.
It's a tricky one to find in higher grades, due to its beautiful (but notoriously wear-friendly) front cover with its dark blue background in the top half and action-packed action scene. Pick a clean copy with white pages and you won't go wrong over time.