I worked with a team once where we did short projects of 2 to 6 months. At first, the plans for these projects were made for us by sales and project managers. Most of our clients insisted on an old-fashioned plan with deadlines, fixed scope and fixed prices. We worked with Scrum but Agile was not such a big thing back then, so most of our clients were rather sceptical about it.
We were forced to compromise, presenting the client with a typical waterfall planning but working on the project using Scrum. To bridge this gap, we looked for new ways to communicate with the client. And we continuously did our best to help them understand the Agile way of working, guided by the Agile Manifesto:
Customer collaboration over contract negotiation