Offer of a menu of different nicotine substitute products to REduce Tobacco Use iN pEople living with HIV (RETUNE): a protocol for a pragmatic randomized trial within the Swiss HIV Cohort Study. - Schönenberger CM; Speich B; Zehnder ER; Haerry DH; Cart-Richter E; Jackson-Perry D; Hutter A; Aggeler S; Steinmann J; Chaudron SE; Calmy A; Cavassini M; et al. (Trials, 2026)