"我们" and "咱们" differ in the meaning of the object. "咱们" must include the listener, and use it to call each other when speaking. includes the meaning of shortening the distance between the two sides. "我们" i can include the listener, and sometimes it doesn't include the listener.

“咱们”包括了听你说话的那一方，“我们”则不一定，可能包括可能不包括看语境。不过其实任何时候你都可以用“我们”代替“咱们”，实际上除了偶尔会看到，我从来没在真实生活中用过“咱们”这个词，一直都是用“我们”的。但是中国挺大的，不同地区讲话的习惯都会有点不一样，甚至有些地区“咱们”也是不包括听你说话的那一方的。

For example，咱们学校 means you and I both in this school. 我们学校 means I and other students are in this school, but you don't.

*Native speakers, please correct me if you disagree with this. When I was taught the difference between 我们 vs 咱们, I was also taught that 咱们 is usually only used in northern(?) China whereas people in southern China prefer 我们. Is this true? Thank you.

அருமை. எனது தாய்மொழியில் எனக்கு அர்த்தம் கூறியதற்கு மிகவும் நன்றி!