1969
The very first time a Marlboro sticker appeared on race driver's racing suit was at the end of 1969: Jo Siffert appeared in a tv interview https://youtu.be/mewlWCvsc_I?t=27 with his 1969 racing suit and a freshly applied Marlboro sticker.
1970
The very first time a Marlboro sticker appeared on a race car was on Jo Siffert’s March 701 during the training of the GP Spain on the 18th April 1970.
Jo Siffert is still the only driver being rather discretely sponsored by Marlboro.
1971
The very first time Marlboro appears on a Non-Formula 1 car was on the infamous STP Porsche 917/10 in the CanAm Series 1971. The car was privately entered by Jo Siffert who was personally taking care of placing the stickers on his car.
Jo Siffert is still the only driver being sponsored by Marlboro. Marlboro was his own personal sponsor.
1972
The very first time Marlboro appeared as a title sponsor was in 1972 with the BRM team. Early 1972 in Le Castellet, the BRM team presented it's new livery.
The contract was signed by BRM boss Louis Stanley on the October 29th 1971 at the Philip Morris headquarter in Lausanne, Switzerland.
That was after Louis Stanley attended Jo Siffert's funeral in Fribourg on the October 29th, just a one hour drive away.
No doubt: Jo Siffert built the foundation of one of the biggest sponsorships in F1: Marlboro.
See https://www.racing-history.info/marlboroIt was Jo Siffert who brought Marlboro into motorsports!