I just saw it fresh in the theatre, so I hope my memory won't fail me. I'll try to put the major ones in spoiler tags and mentioned when I'm not sure. All of these are from trailers and they don't happen in the movie.

Marvel Studios' Avengers: Endgame (Trailer 1)

Captain crying at 01:13

Didn't happen AFAIK

Hallway shot at 01:20

Shown multiple times. Multiple people edited out. I won't mention it in following trailers again.

Nebula standing on a ship at 01:24

Can't remember this scene, but not sure.

Scott doesn't say: "Can you buzz me in?" at 02:20

Big Game TV Spot

Black Widow practicing at shooting range at 00:17

This scene is in multiple trailers. Didn't happen and I won't mention it in the following trailers.

Captain America strapping shield at 00:20

Minor spoiler:

At this point, he had an injury on his arm which was edited out.

Marvel Studios' Avengers: Endgame (Trailer 2)

This is the one with scenes from previous films with highlighted red colour. It also has plenty of lines, which were not said in the film.

Iron Man never said this at 00:03

It seems like a thousand years ago. I fought my way out of that cave. Became Iron Man, realized I loved you

This was also not said at 00:28

The world has changed. None of us can go back, what we can do is our best and sometimes the best we can do is to start over.

Neither was this one at 01:00

I saw all these people die

Hawkeye running at 01:26

This is also a recurring scene.
MAJOR SPOILER:

I think in the movie he ran with Infinity Gauntlet in hand.

Whatever it takes at 01:38

Only Captain America and Black Widow say it out loud in the movie. Also a recurring one.

Thor summoning Stormbreaker at 02:20

He doesn't smile afterwards. You can check the full scene in another TV Spot

Marvel Studios’ Avengers: Endgame | Special Look

Rhodey didn't say this at 00:05

Yeah because he killed all our friends?

No Black Widow in the rain at 00:07

Captain on the ground at 00:45

MAJOR SPOILER:

At this point, Captain shield was broken.

There were lots of differences between the trailer and the movie. Some of which are as follows.

Warning: it has spoilers.

1. Avengers marching.

In the 2nd trailer, we see that Avengers marching wearing quantum suits. This scene was missing in the movie. They don't really march.

2. Missing Hulk

Hulk's appearance was kept secret this time. We see only Bruce Banner not Hulk. In Infinity War trailer, we saw Hulk on Wakanda, but not in the movie. This time they didn't show Hulk, but Hulk is in the movie.

3. Cap's shield

Captain America's shield is shown intact in the trailer, but it is broken during that sequence.

4. Hawkeye running away from an explosion

We see Hawkeye running from explosion holding infinity gauntlet, but this particular scene doesn't appear in the movie.

5. Natasha practicing

We see Natasha AKA Black Widow in the trailer target practicing and punching bags. However, these scenes didn't make it into the movie.

6. Missing Pepper Potts

When Tony arrives on earth, Avengers were waiting for him along with Pepper Potts, but the trailer doesn't show her.

_{Source 1, Source 2}