Before starting it is worth noting :
CSO's are Chief Strategy Officer's
CEO's are Chief Executive Officer's
MD's are Managing Director's
To clarify things and MD and CEO are one and the same, it's just terminology from the UK vs the US - they both are the highest ranking officer in charge of the organisation. Their responsibilities are determined by the board of directors, but fundamentally they lead the company and make the final decisions on it.
In contrast the CSO is purely a strategic role, they generally design, communicate and then help execute the strategy of the business. Their focus is on the mid and long term future of the company, and are sought normally when senior management, especially the CEO, is constrained by the day to day challenges of the business and is unable to have enough time to focus on the long term both in terms of design and execution.
It is a role that can be found in a number of large tech firms such as Oracle and Cisco and nearly always reports into the CEO.