Companies don’t ship software. They ship products. (Or deliver services. Same thing.)
A product has (at least) code, test code, graphics, documentation, training, customer support, marketing, sales, advertising, technical marketing, HR, maintenance, legal, accounting, other products it needs to work with, and a bevy of external partners—alpha and beta participants, investors, administrators, recruiters, third-party developers, book authors, industry writers, competitive partners, customers, and end-users.
And you succeed if the entire product succeeds. Not just your corner of it.
As a project lead, you will most often meet with your peers and direct reports. But you need to know and have a good working relationship with people in each of the roles in the extended team. Your work feeds into theirs and vice versa.
Be sure they have a say in what will be committed to when. And that they feel they have.
Ask how your development team’s ideas impact them. That easy whizbang you want to add at the last minute may be an afternoon’s work for one of your software engineers. But it’s an eng-month for an affected group.
Be open to ideas from any one of them. They may not use the correct terms. What they suggest may reflect a misunderstanding. It’s still worth your time and part of the job.
If you’re not lead, this should matter to you too. If you don’t want the endeavor to be successful, why are you working on it?