Make it happen somehow, will be a cracker of a contest

. If it were to happen some day, practically speaking UAE will be the most likely venue with a 3:2 split between Dubai and Abu Dhabi.
My 2 cents: Pakistan is the best T20 side in the world, no questions, they have developed a ruthless streak and the consistency is not something you expect in such an unpredictable format. India is a flawed side, mainly because of bad team selection. Having said that I will have India as marginal favorites in a long series, may be they will edge it 3-2. When similarly ranked teams (excluding when one of the sides is ATG/GOAT, where ranking doesn't reflect the gap in level) meet it is all a question of match ups. I honestly feel in T20 cricket Pakistan is a good match up for India.
We have the GOAT T20 batsman who takes it a notch higher against the arch rivals in this format, we have 2 lethal weapons in Bumrah and Kuldeep and a consistently high performing top order. Our weak bowling links in T20 won't get as badly exposed as in ODIs/tests because they are good at containing role (Bhuvi, Jadeja) which is effective in this format. Our middle order in T20s isn't as hopeless as in ODIs because they are forced to be more proactive and there is young blood (relatively speaking). Pakistani quicks won't get sufficient help on placid UAE tracks and hence won't be an offensive weapon that can cut through the Indian top order. And once Indian top order is allowed to take control, we all have seen how devastating they can be. Indian batsmen won't be bamboozled by spin unlike other teams and Pakistan will always feel the pinch to take risks in their batting innings because India is a team that can effortlessly pile on 170-180 scores even on sluggish UAE tracks. If risks backfire it will be a stroll in the park for India and even if risks work well and Pakistan puts on a great batting show, Indian batting can match it with a decent chance. Chasing 190 in 20 overs is easier than 350 in 50 overs because of the length of the innings and wickets/overs ratio.
Biggest advantage for India will be in the mental department, a regular Indo-Pak match will be as high octane as a crucial IPL match, current bunch of Pakistanis (barring Malik) aren't exposed to that level of high pressure situations and that may show on the field because nerves play a big part. But still Pakistan will make it very hard for us and rigorously test our weaknesses because not for nothing are they best in the world.
Probably the result will depend a lot on captaincy, while Rohit+Dhoni>Sarfraz, we are captained by a clueless dunce called Kohli who doesn't have an idea about captaining in this format. Whatever he does with the bat will be compensated by his cluelessness as skipper, he will be the biggest ally for you guys if such a series were to arise. Put Rohit as skipper and Kohli as player, I think we will definitely start as favorites because Hitman is a very sharp T20 captain.