Although Stephen Strange has amassed a degree of synonymy with the Avengers since the early 2000s, his original (and perhaps more iconic) team were the Defenders. While that title has been appropriated by Marvel's street-level contingent, there was a time where it was more closely aligned with the publisher's more mystic properties, hence the inclusion of the Sorcerer Supreme.
Created by Roy Thomas in 1971, the original team was comprised of Doctor Strange, Hulk, Silver Surfer and Namor, with the line-up alternating in the years following. One of the more recent Defenders outings, written by Matt Fraction, featured that same roster with the additions of Iron Fist (Danny Rand) and Red She-Hulk (Betty Ross). Those familiar with Fraction's work on Hawkeye and others will have a good idea of what they're in for with the series, and the writer's trademark wit is in full form once again.
What makes the series so important, however, is that it draws mystic Marvel and its cosmic elements right next to each other, much the same way Infinity War is going with the inclusion of Strange, Wong et al.
It's worthy of your time no matter its relevance to Marvel's current film slate and, if you are after more from mystic Marvel, it's the perfect series to scratch that itch.