Analysis of references and co-cited references. (A) The network visualization for the most co-cited references in the field of immunotherapy for brain metastases produced with VOSviewer. The red line represents the time interval of the citation burst. (B) Top 25 references with the strongest citation bursts in the field of immunotherapy for brain metastases. (Hodi FS, 2010 [26]; Margolin K, 2012 [40]; Robert C, 2011 [27]; Chapman PB, 2011 [25]; Long GV, 2012 [22]; Knisely JPS, 2012 [19]; Topalian SL, 2012 [36]; Postow MA, 2012 [41]; Di Giacomo AM, 2012 [33]; Dummer R, 2014 [31]; Sperduto PW, 2012 [32]; Wolchok JD, 2013 [24]; Silk AW, 2013 [42]; Mathew M, 2013 [43]; Hauschild A, 2012 [44]; Kiess AP, 2015 [45]; Borghaei H, 2015 [46]; Larkin J, 2015 [30]; Brahmer J, 2015 [47]; Robert C, 2015 [23]; Twyman-Saint Victor C, 2015 [48]; Ahmed KA, 2016 [49]; Goldberg SB, 2016 [29]; Yamamoto M, 2014 [50]; Tawbi HA, 2018 [35]).