CSK has always been a team which other teams have looked up to, in terms of strategies, player management, and playing style.
Normally then trend in IPL is to make maximum use for the overseas player quota and hence teams used it as a mandatory rule to have four players in the team in most matches.
In the first game of IPL 2019, we saw CSK take the field with just 3 overseas players citing the balance of the team and managed to win the game with that combination. This move surprised a lot of fans, but Dhoni is someone who puts the team's combination ahead of big names and hence was appreciated.
Now we have seen the Delhi Capitals play their second game against CSK, with just 3 overseas players. This tactic that CSK started could very well become a trend in this years IPL and we can expect more teams following this trend.