At a high level, a content strategy defines the criteria for and prioritizes what needs to be created, updated or binned across the entirety of customer touchpoints, including post-sale. As such it’s a cross-function strategy and not just about marketing.
In B2B, this includes (but not limited to) collateral for sales, marketing, retention/upsell, support and CX, partnerships, internal comms
Your content strategy should be born out across marketing disciplines, including content marketing, search optimization, social media marketing, email marketing and so on.
Elsewhere it steers the likes of SaaS knowledge base content, coaching handbooks, partner collateral and how you launch product updates or new services internally and externally.