Congressional oversight of the executive branch is used by the legislative branch to monitor and supervise federal agencies, activities, programs, and the implementation of policy. This process is Congress's way of checking the powers of the president and other executive agencies.
Over the past two years, the Democratic Party had control of the executive branch while the Republican Party had control of the majority of congress. This caused for a lot of tension between the two branches as the party platforms have many differences. The president could check the doings of congress by deciding to veto their legislation. However, in order to slow the policy making of President Obama, congress used their power of oversight. Some key legislation congress slowed Obama (and the democrats) from passing include the DREAM act for young immigrants, the expansion of benefits for homeless veterans with children, and some parts of the Affordable Heath Care act. It is estimated the only 51.3% of Obama's campaign promises were honored throughout his presidency, potentially because of the inhibitor of congress.
In 2017, the republicans took control of the White House and maintained control of the majority of senate and house seats. Since both branches are supporters of the same platform, their is a higher trust profile between the two branches. President Donald Trump has proposed many regulations and policies that are also in Congress's interest such as increased border protection, a ban on lobbying in the White House, and regulation reform. The legislative branch is less likely to want to slow the passing of these bills by reviewing every single detail because it is likely that when midterm elections come around, the democrats may be able to regain control of congress and will for sure slow the implementation of Trump's policies. For the next two years, congress will not be exercising as much oversight as they did in the past because they want to further the republican platform.