Tendulkar has two major advantages over Kohli at the moment:
- Tendulkar's peak was at a time when bowling standards, both pace and spin, were much higher than today, which gives his achievements a special glow.
- Tendulkar's fairly flawless record in and against different countries over a long stretch of a career.
For Kohli to to counter the above, he basically needs to keep up what he is doing (outshining his colleagues against the few world class attacks like SA, Australia and England in their own countries, and score daddy tons against the weaker attacks and at home). If he can continue his current form until 100 tests or so, and along the way score 1 or 2 career-defining innings (like Tendulkar's 155 against Australia or 136 against Pakistan) then I think he would justifiably merit comparison. If those innings were match-winning innings, like a successful 4th innings chase, that would give him an edge since Tnedulkar wasnt very strong in that category.
If he were to retire tomorrow, he would deinitely find a place in an Indian All-time Test XI, but Tendulkar would rank ahead of him.