You can move in there with a little shove and go in further on his reaction.
IF he leaves the jab arm hanging out there and only half cocks it and shuffels along from behind it : Or if you can time the end of his jab by safe distancing yourself as it comes; you can take his elbow point as it returns with a glove from the outside and shuv it into him or over towards his other arm as you safley move into the inside range.They react to a shove and youre attacking arm goes around the reverse way to the reaction and attack up the gap with your free arm or loop the pusher arm around it into an uppercut. Your in there then.

IF you can reach his elbow point with a glove he cant reach your face or body with that hand, the control is placed briefly right there as you move in further. Some great natural instinctive combos can come out of it.

Sometimes you have to move to the outside of his jab bodily.
Sometimes it doesnt work well at all like on a rising type snapping jab but you can still jam it up the same way if you follow it right back home and stay more to that one side.