What do Atticus and Miss Maudie both point out about Tom's trial that leads them to believe racial injustice may be lessening?

Miss Maudie and Atticus both point out it is a sign of progress that the jury actually deliberated in the Tom Robinson case. 

Maycomb is a town deeply divided by race. Most white people in the town think there is absolutely nothing wrong with racism. It is just the way things are in their town. When Tom Robinson is put on trial for the rape of a white woman, things really come to a head. 

At first, the town opposes Atticus for defending a black man. They assume if a white man accuses a black man, then the black man must be guilty. Therefore, when Bob Ewell says Tom Robinson raped his daughter, Bob must be right. White people believe they have to stick together, and at that time only whites could be on juries. 

At the trial, it becomes clear the rape never happened. Bob Ewell beat up his daughter when he saw her with Tom Robinson and accused Tom of rape to cover it up. Atticus proved all of this, and the prosecution never proved the crime occurred.  

Still, Tom Robinson is convicted. Surprisingly, however, the jury actually deliberated. Miss Maudie explains this is progress, as the verdict is usually returned quickly in cases like this. 

Atticus Finch won’t win, he can’t win, but he’s the only man in these parts who can keep a jury out so long in a case like that. And I thought to myself, well, we’re making a step — it’s just a babystep, but it’s a step (Chapter 22). 

Jem is very upset by the verdict because he followed the evidence and felt Tom should win. Atticus explains to him that race was a factor in the decision. Winning wasn’t really possible. 

Tom Robinson’s a colored man, Jem. No jury in this part of the world’s going to say, ‘We think you’re guilty, but not very,’ on a charge like that. It was either a straight acquittal or nothing (Chapter 23).

Atticus did tell his children before the case that it was essentially unwinnable. 

“Atticus, are we going to win it?”

“No, honey.”

“Then why—”

“Simply because we were licked a hundred years before we started is no reason for us not to try to win,” Atticus said (Chapter 9).

Atticus was right. He explained that there were people on the jury who believed Tom was innocent, including one of the Cunninghams. This, according to Atticus, is progress toward racial justice.