Chief of Defence Staff (CDS) is a post that acts as the single-point advisor to the Government of India in the matters of India’s military. The CDS is the head of the Army, Navy and Air Force and is be a four-star military officer. He/she is in a position to advise on the matters related to all the three segments of the military. The appointment of CDS aims to make India's armed forces integrated.

Indian Army chief General Bipin Rawat was appointed the first Chief of Defence Staff (CDS) on December 30, 2019.
The recommendation for creating the post of CDS was first made after the 1999 Kargil War. A high-level committee that was set up to examine the gaps in the country's security system in the wake of the Kargil War had recommended that the three services should have a Chief of Defence Staff.
The committee had said this person, a five-star military officer, should be the single-point military advisor to the Defence Minister. After that, a Group of Ministers (GoM) recommended the appointment of CDS in 2001. But it was made public in 2019, when Prime Minister disclosed the government's plan to appoint a Chief of Defence Staff on August 15 in his speech from the ramparts of Red Fort on the 73rd Independence Day.
Why was CDS needed?
In the article - "The way forward in military command", defence expert and Business Standard columnist Ajai Shukla said  that “appointment of CDS would unquestionably make the military leaner and more effective. In many ways, this would mirror the US system, which has functioned admirably through inter-continental global challenges.”
The case for a CDS has been built around the argument that it is necessary to have a professional body to render single-point military advice to the government on matters of national security.
When did the appointment of CDS become necessary across the globe?
Within a few years after the Second World War, the appointment of CDS was made at the national level in many countries, but not India. Some countries use different names for this appointment but the functions assigned are the same. In the United Kingdom, the post was created in 1959 to reflect the new concept of joint operations that had come to the fore after the war.