Different things for different situations; more of them arise in mma.

Half steps and control of his arm is one way to think so you can release and go in all the way once your safe.

If their jabs out and feeling for you ,Take them at the elbow point on the way in and and slip their reaction.

Double up the jab on the way in.(use the first as a feint) or an attack.depends on if your footwork is with the move or just behind the move.

Even attack their lead arm under the elbow with a punch and then double up as you move forwards. Like an upper cut the centre of their lead arm and then go over the top as they react downwards and you move in on their reaction.

Go real low and come up under them on either side of that lead arm, requires angled footwork and have their knee checked or catch them off footed so you dont walk into a knee to the face.

Time their jab, move out of range but check it softly with a glove then follow their arm back to load position controlling that side with your check glove by pushing straight out as you move in, footwork is like picking up the weight off your front foot (so that the jab misses you by a smige and as you land you are in range yourself and you have his lead arm pressured the whole way back.you just got to have his other arm in sight. You'll feel any kick comming through his arm and can pull it down which stops the kick dead.

Switch stance so that you bodily go around his jab either by pulling your lead leg back around behind you but then instantly shuffle forwards so that you go up the outside edge of his same arm but control his arm whie you do it so that you can pull it down if his knee starts to rise again.If you can get to there they always turn around to face where you just went and thats when you land the bomb.

Or if you can get his jab to start going over your head skip forward and open up your feet attacking him with your rear arm on the way through to your own reach; Or a knee up into his ribs under his arm if the opening arrises or if you can get under there like that and catch him reaching out for you, sort of a skip off the front foot double arm grab and pull him into a knee right through the rib cage.