Found published work that doesn't reference previous related work I have been researching a specific topic in computer science for a couple of years now and a well established professor and his students have recently published a couple of publications in that topic too. In their work they do reference the well known and well cited previous work that basically everyone in that topic references, but I have noticed that they ignore (don't reference) a couple of publications that are doing essentially what they are publishing about, i.e. extremely related work. And I am wondering even though there is a gap of a couple of years between the work they have published and the available previous literature how did they miss referencing the relevant previous work? Was it done intentionally or did they just do a hasty job at finding more recent related work?

Either way my main concern here is if there is anything that can be done to remedy the situation now, since the paper has already been published?
Realistically, there is nothing you can do to change an already published paper. There are some options for extreme cases, but they are unlikely to apply.

What you can do is try to have the record correct in future publications. Unless you have hard evidence to the contrary (and usually even then), it is best to communicate on the basis that this is not an act of malice. You can write the authors of these papers (and authors of preprints on the topic) a polite email stating that you liked their interesting work and have done related work that you think might be of interest to them. What they do with that information is up to them then.