Finally, before the debate, we asked likely voters what issues would have the most impact on how they’ll vote this fall. (Respondents were allowed to select up to three issues from a list of 18.) The most common response was inflation or increasing costs, which 50 percent of likely voters cited as one of their top issues. That was followed by immigration (37 percent) and political extremism or polarization (25 percent).

The debate doesn’t seem to have changed Americans’ views on which candidates are better equipped to handle these issues. As they did before the debate, likely voters (both debate watchers and non-watchers) said Trump was better able to handle both of their top two issues: inflation or increasing costs by a 55-percent-to-45-percent margin, and immigration by the same spread. However, voters believe Biden is better able to handle political extremism or polarization, 56 percent to 44 percent, as well as the next-most cited issue on the list: abortion (57 percent to 43 percent).
https://projects.fivethirtyeight.com/biden-trump-june-debate-poll/